US equipment is already scheduled for several HP
Beginning April 2, US will operate RDU
turns as part of the Vegas night hub, with A319s that would otherwise RON at Raleigh/Durham or Miami.
Also on April 2, America West will initiate a third frequency from Philadelphia to Seattle, routing another RON HP A320 from PHL-SEA-PHL as a redeye.
Right now the limiting factor is the lack of interoperability - HP pilots have to stay with HP planes and vice versa. Once the certificates and pilot seniority lists are merged sometime in 2007, I'm sure you'll see a massive rescheduling of aircraft routings to keep the jets in the air as much as possible.
[Edited 2006-03-21 10:41:55]
USAir A321 service now departing for SFO with fuel stops in CAK, COS and RNO. Enjoy your flight.