Have you checked out the transit type buses? They tend to have a much more square roof line and also tend to sit lower to the ground. Also from what I have read they err on the side of too much A/C, which is a really good thing here in DFW.
There seem to be 2 big players in bus auctions here in DFW:
I got my bus from Arlington ISD a few weeks ago through Rene Bates. They don't charge sales tax or a buyer's premium (of course you pay the state the taxes later, can't escape taxes) There is probably more auctions but these 2 seemed to have the majority of the buses. We are building our bus to transport us and our dogs to markets to sell our stuff as well. (Nothing more fun than loading glassware in and out of an xb)
In any case, welcome to the forums and fun!!