Depends on what you are looking for....  A portable unit or a mounted unit.

If you are interested in a portable unit that is quiet and loads of power I would contact Southern Plains Cummins /Onan in Arlington, Texas and buy a Cummins/Onan P4300ie.  Since you are with in a hour or so of Ft.Worth you could pick it up and save the shipping.  They also carry the mounted units as well.

I bought the P4300ie and set it in my first stall for now and used it for the first time last weekend and just opened the escape door, plugged it in and run it.  Was not really warm enough to need the a/c yet, just wanted to check it out and make sure it was quiet enough to leave in the trailer.  IT IS!  And it is much less noise than the Onan microquiet that was own our last trailer.

Here's a list of RV salvage yards... They may have something...  http://www.ccis.com/home/mnemeth/rvsalvage.htm

http://rvbasics.com/techtips/oldparts.html