Robert Christ in Mesa has a varied selection of units. They are on Main St in Mesa. There are also a bunch of dealers right around them to look at. Be there a week day and start about 10:00. That area should keep you busy for the rest of the day.
Also, on most weekends here, La Mesa RV has a "show" at University of Phoenix Stadium off the 101 freeway. It will be a hike from where you are going to be, but they usually have quite a few units.
If you plan on the U o P Stadium show, while you are out that way, check out Orangewood RV and Sun City RV for multiple options.
Happy Hunting!