FOR ONE BRIEF shining moment, I really thought I had invented something.

What if photographers who do a lot of location work and who wind up schlepping heavy camera bags on their shoulders -- misaligning their spines, throwing out their hips and punishing their feet -- had a case that was a grown-up version of the rolling luggage that members of flight crews have been casually wheeling through airports for years?

My bag -- the Frankie Bag (after camera bag guru Jim Domke's Domke Bag) -- would be rugged, of course. Its two distinguishing features would be heavy-duty rubber wheels and a retractable handle that would disappear into the body of the bag when not needed. There'd also be a conventional, but very heavy-duty, luggage handle for those few times when you (or preferably, your assistant) would actually have to lift the thing. Inside would be modular padded inserts so that you could customize the case to fit your equipment.

I had this idea over the summer and had visions of calling Jim Domke and having him say, "Jeez, Frank -- may I call you Frank? -- that's a fantastic idea. Where should we send the royalties?"

Then I made a few real phone calls.

I didn't want to be rich anyway.

Just as camera fannypacks became all the rage several years ago, just as camera backpacks have enjoyed a wide popularity recently, so have rolling camera cases starting popping up in camera stores like so many mushrooms in a cold dark basement.

And with good reason. The idea solves a common problem of many location shooters: dealing with the roly-poly cart on which you have bungee'd, tied or otherwise taken hostage, all your precious bags of camera gear. It may not sound like much, but it's something that gets my goat whenever we go on location, especially to an office building to shoot a portrait or a series of photos for a brochure or annual report. Out in the boonies, the roly-poly handcart works fine, but in the button-down business world, I always feel like a camera-toting homeless person lugging all my worldly goods behind me on a metal cart that always seems to be getting in the way while we work.

Of the rolling cases I've seen, easily one of the best in Tamrac's Rolling Strongbox, a handsome and rugged affair that easily can carry multiple camera bodies and lenses. The Strongbox shown in Tamrac's new brochure, for example, contains two Hasselblad bodies, two Nikon Bodies, five lenses, a small flash unit and a light meter -- not to mention all the space in the bag's WindowPane Mesh zippered top for filters, cords and other small necessities, like, say, film.

This "strongbox" with wheels and "industrial strength" retractable handle is actually a logicial extension of Tamrac's earlier and highly regarded regular strongbox -- basically a soft-sided nylon shoulder bag whose top and sides and have been rigidly reinforced. Listprice on Tamrac's rolling bag is $399. A similar rolling box, the Zeroller, is being offered by Zero Halliburton. This maker's hardsided, beautifully detailed, aluminum cases are widely viewed as the Fort Knox of camera bags. List price on the Zeroller is $378.

Not to be outdone, though its case is not in the stores at this writing, is Lowepro of California, a company known for its hard-wearing, innovative camera cases. A spokeswoman for the company told me "we are working on a design" for a rolling camera bag and expect to have one out in a the near future.

If imitation is the sincerest form of flattery, however, the PorterCase folks of South Bend, Ind., are trying to do their imitating on the low-end side -- offering their own rolling case at half the price of Tamrac's, but with nowhere near the ruggedness.

In looking over this bag at one local camera shop, I could not help but be reminded of inexpensive luggage. The case had a thin plastic exterior that gave easily when I pressed down on it, an anemic foam-lined interior and a retractable handle made of tubular metal. What impressed me the least, though, was the case's woefully inadequate handle -- basically a thin piece of plastic held onto the case by two small rivets. I'll give PorterCase credit for trying to fill a niche in the market, but I doubt this bag could stand up to any prolonged, hard use. I wouldn't risk my gear in it.

* THERE'S STILL time to see some of Sam Kittner's beautiful photographs, through Sunday at the Savory cafe and gallery, 7071 Carroll Ave., Takoma Park, 301/270-2233. Included is work from Kittner's "Capitol Ruins" series -- striking photographs of ornate stones from the Capitol building, discarded in a little-known area of Rock Creek Park during construction of an extension to the original building in 1959.

* POLAROID WORKSHOP: Tina Williams will host another of her popular Polaroid image transfer workshops, Nov. 13 at 3 at the PhotoGroup Studio in Silver Spring. Sponsored by Polaroid and Penn Camera, the six-hour hands-on session will cover advanced subjects like 8-by-10 image transfers, black-and-white transfers, emulsion transfers and more. The cost is $199. Call 301/210-7366 for reservations. Frank Van Riper is a Washington-based professional photographer and writer.