I could see them using the US Air name over America West, too. Brand recognition is gold when you're looking for airline tickets on-line. I've lived in two cities HP flew into, and everytime I was looking at ticket prices, I totally forgot about them. Funny thing is, they're often cheaper than SWA from MCO-LAS.
As far as Mesa, I'm sure JO is creaming on himself over this deal. Mesa does a LOT of flying for HP (um, I THINK they might do ALL of the regional flying for HP, Bog?), and they'd love to keep their planes in the US Air system instead of parking them and losing money. Wouldn't surprise me in the least to see Mesa throw money to get the deal sealed. Not sure if they have enough money on their own to lock it up, though. Maybe call GE since they seem to be handing out airline bail-outs like candy.