What sounds like an ambitious schedule for any four-man framing crew becomes routine with one simple ingredient: factory-made wall panels. With these panels - already squared and sheathed - and with factory-made roof trusses, Lot No. 187 in Maiden Creek Estates in Maiden Creek, Pa., will go from completed foundation to completely framed 2,200-square-foot house in 2-1/2 days. Project foreman Hank Mengel rolls his eyes when asked if he'll ever go back to stick-building. "Oh, no," he says. "Never." It's no wonder. At Maiden Creek Estates, crews are framing a house in half the time of stick-building crews down the street. In a competitive area like this, speed is important. So are quality and cost containment, and Mengel says the