The Gila river in NM is a good trip. I'm not sure if you will find any outfitter, but you could maybe hook up with a private trip. Also the San Juan at Mexican Hat in NM, but that requires a lottery permit. The Salt in AZ is awesome. If you include Utah in your search you add several sections of the Green as well as Cataract Cyn and Westwater Cyn of the Colorado. Also in the Southwest corner of CO near Cortex the Dolores is supposed to have a release this June and is a 5-6 day trip.