Bear in mind that weight may be the limit on some C's, especially ones with longer rear overhangs. There may be plenty of volume, but rear axle or total allowable weights may keep you from using all of it. Even some short RV's are weight-challenged.
Jim, "Mirror, mirror on the wall, what the flamin' heck happened?"
'06 Tiger CX 'C Minus' on a Silverado 2500HD 4x4, 8.1 & Allison (aka 'Loafer's Glory')