TOWNE WITHOUT PITY: Hugh Hudson has begun work on his first film since "Chariots of Fire." "Greystoke: The Creation of Tarzan and His Epic Adventures," began shooting last week in Cameroon, West Africa, and will move to other African sites before wrapping up in Great Britain. The screenplay is attributed to P.H. Vazak and Michael Austin: the latter scripted the widely dismissed "Five Days One Summer," and you won't find the former listed in any screenwriting directories. Vazak, insiders say, is a pseudonym for the persistent "Personal Best" director/writer Robert Towne, who began writing "Greystoke" six years ago and lost his rights to make the film in some confusing, bitter bargaining. "Robert was hoping that 'Personal Best' would be a big hit and he'd have the clout to get 'Greystoke' back," says one source close to the director. "But it wasn't a hit at all, so Warner Bros. gave his pet project to the guy whose sports movie was the absolute opposite of Robert's sports movie. He's got to be cringing every time he thinks about it."

FAST FRAMES: Last May, director Walter Hill began shooting "48 Hours," a comedy/drama about two policemen -- Nick Nolte and Eddie Murphy -- forced to work together for two days. Last September, Hill assembled his first rough cut. And last week, an audience in Long Beach got the first look at one of the speediest major studio films to be released in some time. Hill doesn't always work quite that fast -- "The Long Riders" and "Southern Comfort" took considerably longer, though "The Warriors" was another rush job. But, says one source, "Paramount needed a Christmas movie, and they gave him the money if he'd get it in that fast." The film -- and Murphy particularly -- went over well with the preview crowd, but Paramount has yet to come up with an ad campaign. "They can't quite figure out how to advertise it," says the source. "It's mostly a comedy, but it's a comedy with lots of Walter Hill-style slam-bang stuff."

STUDIO ROULETTE: Jim Brooks figures to have some clout in Hollywood these days since, among other things, he created "The Mary Tyler Moore Show," "Lou Grant" and "Taxi." But Brooks had his share of problems trying to make his directing debut with "Terms of Endearment," a comedic drama finally slated to shoot next year, with Shirley MacLaine and Debra Winger starring as a mother and daughter who age 25 years in the course of the movie. Based on a Larry McMurtry novel, the film originally was scheduled to be made for Paramount, which okayed the project but refused to go over a $7.5 million budget; when Brooks decided he couldn't bring the film in for that figure, he went to United Artists, which agreed to supply whatever money it took. Then Freddie Fields took over the reins at UA, and suddenly that company passed on Brooks' project. Now he's back at Paramount making the movie. The budget? $7.5 million.

SKY'S THE LIMIT: Two weeks ago, "Airplane II, The Sequel" was shown to an enthusiastic preview audience in San Diego. Less than a week later -- and still a month before the film's release date -- producer Howard W. Koch was given the go-ahead to begin work on "Airplane III." Through it all, the original film's creators and directors have remained critical of the sequels; Jim Abrahams and David and Jerry Zucker say they'll have nothing to do with any sequels, that cloning a hit movie is unimaginative and dull. But it's also profitable, hopes Paramount: The first "Airplane" cost a mere $3.7 million and took in more than $75 million in rentals. The second "Airplane" cost twice as much to film -- plus the additional $2 million it will cost to make the huge number of prints required to put the film in 1,400 theaters come Dec. 10.

NAME GAME: A Beverly Hills production company has just obtained worldwide distribution rights to "Khan Asparouch," a lavish, battle-strewn, six-hour Bulgarian epic about the father of that country. Hardly the stuff of which usual movie hits are made, so some changes are in the works. It will be cut to 110 minutes, dubbed in English, given a new musical score and retitled "681 A.D.: Revenge of Khan." Any similarity to the title of the last "Star Trek" film is purely coincidental. Maybe. It's just that, the father of Bulgaria notwithstanding, "Revenge of Khan" sounds a lot like "Star Trek II: The Wrath of Khan," and even more like that film's original title, which was "The Vengeance of Khan." That title, by the way, was changed because it sounded too much like George Lucas' "Revenge of the Jedi," the upcoming "Star Wars" sequel. Which sounds a lot like "Revenge of Khan."