So far, the only success downtown's Shubert Theater has enjoyed is as a public engineering project--a nifty $4.7 million exercise in lifting and hauling. In the meantime, a pair of unreconstructed cineastes, previously prosperous in the field of ice-cream sales, have been turning a $155,000 theater into the most unlikely of art houses. When Tom Letness and Dave Holmgren bought this 1926 theater a few years back, its stock-in-trade was the film business's third-run leftovers. Drawing funds from the hot eats and cool treats next door--a Dairy Queen franchise that the pair owns--the Heights has shed its nasty turquoise aluminum siding for its original brick façade. On the inside Letness and Holmgren have installed a 70mm projector, an improved sound system, and a host of antiquated projection devices the duo encountered in their previous sideline as collectors and dealers of movie hardware. With these handy gadgets, the Heights has screened such rare wonders as a 70mm print of Lawrence of Arabia, a silent and previously lost Frank Capra comedy, and a regular series of Hindi-language blockbusters that has packed the 400-seat theater. On top of the newly painted main room and rehabilitated lobby, the Heights now features a handsome retracting curtain, and decorative drapes rescued from a 1920s theater in Grand Forks, North Dakota. Perhaps the most glamorous project, a Wurlitzer theater organ, has been coming together in pieces--a pipe or two at a time--from sundry auctions and widows' basements. Its possible installation this fall could provide the perfect fanfare for a singular old/new theater.