Finding optimal Motorhome

http://www.ebay.com/itm/DT466-AUTO-TRANS-4X4-4-WHEEL-DRIVE-CAB-CHASSIS-STRAIGHT-FRAME-DUMP-UTILITY-TRUCK-/381808421461?forcerrptr=true&hash=item58e58e2a55:g:~GgAAOSwKfVXLPSS&item=381808421461

Something like this, mount a service body and a slide in camper, done. Plenty of room for large capacity tankage, genset and battery bank.

Or this

You are not going to get the clearances you need, particularly departure angle, with any conventional rear-engine diesel motorhome, because the drive train is relatively long and mounted very low in the chassis to make room above for the house. Because of the length behind the axle needed for the drivetrain, the shortest you will find might be around 32 feet, long enough to get wheelbase close to half of overall length, and put some weight on the front axle for balance.

Off-road motorhomes tend to be built on Class 5 to Class 7 truck chassis, and mostly built above the chassis without basement storage, so that none of the house reduces ground clearance. Earthroamer XV/LT is about the closest model to the size you've specified, though you'll find much larger (35-45 feet) expedition vehicles built on heavier military truck chassis, from specialty builders like Unicat, Global Expedition Vehicles. The Tiger line from ProVan Industries has some smaller options, although their larger models overlap the Earthroamer XV/LT line.

All of these are in the nature of a permanent, rather than slide-in, camper box on an off-road truck.

Class A motorhomes, diesel pushers particularly, are built for the highway and the RV park.

Coldchuck, after rethinking about your post there is a motorhome with ground height. I haven't seen one around in a while there called a El Dorado. The cab and chassis are made by Freightliner! It's a semi truck with a motorhome body on it. I don't know what lengths they are built in. This motorhome can get you up and down any type of road that a logging truck could run on.

Diesel Pushers are built for highway comfort!

There are few if any short diesel pushers. A large part of this, as I understand it, is because the amount of space in back of the rear wheels required for the engine and transmission would force the rear wheels to be too far forward on a short chassis.

I know you weren't really interested, but a good few class C's are somewhat better in terms of ground clearance than most class A's. They still are far from exceptional by and large, the departure angle especially being a poor point thanks to the long overhang in back. Class C's based on a van chassis also often have a pretty horridly large minimum turning radius.

Perhaps your best bet would be to convert a smallish school bus. They are generally designed to be able to go over less than perfect roads, and in rural areas often do travel over dirt and gravel roads. Making an RV conversion is a whole lot of work, of course.

I use to have a 2002 Fleetwood Flair 25Y,{26ft}, sort of miss it because it was easy to drive, set up high like you want, no slides so could be made to go off road just not ruff off road, had everything, queen bed, nice bathroom, dinette and passenger seat swiveled around, TV's in front and back, 100 gal fresh tank, 65 gal fuel tank and large outside compartments.

However it is only on a gas chassis, mine was the Workhorse with the GM 8.1, very strong running since it only weighed 12,000 lbs.