THE SHAH of Iran is not the only royalty looking for a place to settle these days; his friend Leka i is another. Leka, king of the Albanians, is the revolutionary activist among the 12 claimants to European thrones no longer existing. At 39, he is chairman of the Council for the Liberation of Ethnic Albania -- a region which includes sizable portions of neighboring Yugoslavia and Greece -- and commander-in-chief of the armed forces under that council's authority.

In February, Leka was expelled from Spain, where authorities suddenly raised objections to his large cache of weapons in his residence on the gentle slopes of Pozuelo, a village some 10 miles outside Madrid. He explained that the weapons were for his own protection: Apart from Albanian agents, there is now a Maoist terrist group of Spaniards, with members trained in Albania.

Leka is Moslem, speaks Arabic and appeals to Islamic solidarity. He tells conservative Moslem rulers that he is determined to liberate Albania, the only European country with a Moslem majority, but one which shut down all mosques and churches in 1967, declaring itself "the world's first atheist state." Leka leaves his visitors with the impression that the secret military training bases he says he has in various countries are in Arab states. Emigres suggest that Leka is referring to his loyal followers among an Albanian diaspora of some 3 million souls, close to 250,000 of them in North America and the majority in Yugoslavia, Greece, Italy and Turkey.

Albanians are natural soldiers, emigres add, and Leka's loyalists are led by old tribal retainers. He spends much of his time visiting them. On a North American tour last winter, Leka was arrested briefly in Canada for carrying a concealed weapon.

Leka is an international arms dealer. While his Massachusetts-sized homeland is on the Adriatic coast, his primary base of operation has been some 10,000 miles away, in Thailand. For the past 10 years, he has gone there several times a year to buy Chinese and Russian arms and to recruit Shan tribesmen -- the fabled guerrilla fighters of the hills -- to train his liberation army. "I went that far in search of an ally," he told me in an interview, "because I wanted an ally with whom there can be no clash of interests."

Shans who join his forces learn Albanian and take up Royal Albanian citizenship. Leka is lyrical when describing the surprising similarities in history, customs and mentality between his two mountain peoples, one from the pine forests of the Balkan and the other from the jungles of Indochina. Eroding status

For the past 15 years, Leka has maintained a court in Spain, issuing Royal Albanian passports -- including his own -- and, under Francisco Franco, enjoying diplomatic privileges. But his special status gradually eroded as Spain's relations with communist countries solidified under King Juan Carlos, who nevertheless invited his old friend Leka to receptions honoring visiting royalty.

When I visited there last November, Leka's residence looked more like a military camp than a royal court. It featured a row of prefab army barracks, areas for target practice and other military exercises as well as a suburban rambler, his home. The rambler had functional modern furniture and sumptuous Persian carpets. Antique rifles, daggers and spears from all the continents covered the walls. The compound was surrounded by a 6-foot-high chain-link fence and protected by armed guards, Albanians and Shans dressed in the uniform of his liberation army.

When Spanish authorities threatend Leka with confiscation of his arsenal of machine guns and hand grenades, Leka and his retinue of some 20 people left on a chartered jet. Leka said he might go to Morocco -- whose King Hassan II he counts among his friends -- or to Argentina where there is a small but important Albanian community. But the party landed in Gabon officials refused to permit Leka to leave the plane. After a few hours of fruitless negotiations, Leka ordered the plane to take off and to cross the continent to Rhodesia.

A student of guerrilla warfare, Leka had been a frequent visitor to observe fighting in Rhodesia -- as well as in Angola and Mozambique during Protuguese rule. In Rhodesia, Leka has many friends, including Foreign Minister Pieter van der Byl, a hunting companion of several years' standing.

But Fhodesia is a temporary asylum, and Leka, like the Shah, has been contacting other friends elsewhere. Born to exile

Leka has been in exile since he was two days old. When fascist Italy invaded Albania in 1939, his parents, King Zog and his Hungarian-born Queen Geraldine, fled across the mountains to Greece. They eventually reached England, where kings and cabinets banished by the Axis powers congregated. But after World War II ended, it was another exile, French-educated Enver Hozha, who seized power in Albania, setting up a people's republic. He is still undisputed ruler.

King Farouk -- himself of Albanian descent -- invited Zog and his family to settle in Egypt. But Gamal Abdel Nasser's revolution deposed Farouk, and Zog, who had established himself in the export-import business as well as in small arms manufacturing, was forced out again, this time to Cannes.

Leka went to high school in Alexandria, Egypt, and attended Phillips Academy at Andover, Mass. He studied economics at the Sorbonne and military arts at Sandhurst. After Zogs death in 1961, Albanian emigres from throughout the world gathered at the Hotel Bristol in Paris and acclaimed Leka their king -- or, as the Albanian phrase goes, Chief of the Sons of the Eagle. Albanians call themselves Sons of the Eagle.

In 1975, Leka married Susan Cullen-Ward, daughter of a wealthy Australian sheep rancher. That was also the year Leka's army claims to have infiltrated Albania for the first time -- to find out if conditions were favorable for libertation. The report brought back was in the affirmative. In the next two years, one unit staged a rocket attack on the Albanian embassy in Paris and another penetrated Albania's coastal waters and blew up communications cables linking the country to Italy.

After breaking with the Russians in 1961 and with post-Mao China in 1978, Albania has begun a cautious campaign to open up trade and communications with a select group of Western countries: Italy, Austria, Sweden and the Netherlands. A trade pact is now in force with Greece, and there is a weekly air service between Athens and the Albanian capital, Tirana.

Albania has made overtures to the United States as well, and President Carter may be able to chalk up among his foreign policy breakthroughs a normalization of relations with Albania. Some American Albania-watchers suspect that Leka's abrupt fall from grace in Spain may be connected to moves preparing for that normalization.

Another theory offered is that the CIA and Thailand no longer look upon Leka with favor. According to a knowledgeable American source, during the Vietnam war Leka purchased arms and intelligence information from Shan tribesmen crossing into China and then sold it to the CIA. In the early 1950s, CIA efforts to liberate Albania involved officers loyal to Leka's father. But the operation was doomed from the start because it was coordinated, if not actually devised, by Kim Philby, then Britain's man in Washington and later unveiled as a Soviet agent.

Leka has only contempt for the CIA, which, he says, engineered his arrest in 1975 in Thailand. The objective, he says, was to discredit him with Ablanians at home and in exile. It took Leka six days to arrange for his release from a remote provincial jail. He was subsequently charged with arms smuggling; his defense was that he needed communist-made arms for his liberation forces. He was acquitted. The right climate

Leka believes that the climate of opinion in Albania is ripe for a revolution and that his forces would be received with open arms. "My biggest problem," he says, "is whether to attack before or after Tito's death -- the next great upheaval in the Balkans."

Leka stands 6 feet, 9 inches -- a giant of a man with a face that recalls an American teenage idol from the 1950s. He has blue eyes, broad shoulders and a comfortable paunch. Dressed in green army fatigues and speaking in idiom of John Wayne, he struck me as a Fidel Castro of the Right, a Tito or royal blood. His is the youngest royal house in Europe, and, like the shah, his is second-generation royalty. No sophisticated decadence mutes his urge to conquer, and his is the raw primeval essence of kingship: the mighty warrior leading his tribe into a battle against the usurper.

In official Washington, a mention of his liberation army raises skeptical eyebrows, and his business connections elicit snide comments.

"But even if you take him seriously," one U.S. official gave as the bottom line, "no small band of irregulars can succeed against a government any more. Castro was the last man to pull such a coup."

Conventional wisdom and computerized intelligence do not have a good record in sizing up the strength -- or the despair -- of determined groups. As we learned in Iran most recently, a revolutionary mood still cannot be reliably quantified, or its momentum reliably predicted.

Should Leka return to his homeland one day, it would be despite and regardless -- rather than because -- of Washington, or Moscow. But then an enterprising reporter will be able to use the line: "The Eagle has landed."