I just pulled the trigger and ordered a Pentax smc DA* 16-50mm F2.8ED AL [IF] SDM lens from Adorama. $659.95USD was just too good a price to pass up, especially with this weak dollar.
Update 1: UPS should be delivering it any minute now. Opening this box and testing the contents will be a lot like looking at Schroedinger's cat; I don't know if this copy of the lens is a dud (too many have been) or a gem.
Update 2: Got it! Looks good so far, but no extensive tests yet. I also got a Pentax IR Remote Control F - that thing is tiny!