If you need ground clearance you also want to minimize the rear overhang. Unfortunately, most short class A's have the 158" wheelbase usually giving a poor wheelbase/length ratio and longer than necessary overhang. I've never had one but in addition to the overhang problem some report poor highway handling.
As some above mentioned, one exception with a great W/L ratio is the Thor Vegas/Axis line but you would want to stick with the E-450 models, not the E-350. It has less ground clearance than an F53 class A as it is just a class A built on an E series stripped chassis. You could, I suppose, get a company like
www.ujointoffroad.com to do a 4x4 conversion and lift since it is an E series. Not sure how the Thor house would hold up off road.
If you are looking used, don't be misled by the one in my signature. The specs say it is 27'7" but it is 29'7". It still has a great wheelbase 208" for a shorty.
2007 Tiffin Allegro 28DA