Last August, Mayor John Hickenlooper got everyone's attention with the announcement that the City of Denver had agreed to receive the paintings and drawings in the estate of abstract-expressionist master Clyfford Still. The multimillion-dollar gift from the estate's trustees was made in exchange for a promise that the city would build a museum to display the collection. So far, no architect has been selected to design the building, nor has a site been picked out. But fundraising is well apace, and Dean Sobel, former head of the Aspen Art Museum, has been hired as director. Sounds like a wish is rapidly becoming a promise.