Perhaps the space below could be used for something even better, like the “claimed” first bike garage in North America in a compact Class C below 25 feet. I just saw it for first time this morning.
The bike garage doesn’t look tall enough for road bikes or most tandems, but I certainly hope the idea catches on with mainstream manufacturers. The prototype below is on diesel Transit with long wheelbase, and has odd floorplan. The bike garage is what I think Thor should have been offering on Axis 24.1 all along.
Bob, regarding your point, most of those items are generally mounted by RV manufacturers outboard of main chassis rails, except fresh water tank which is often inside, or grey/black tanks in middle of chassis at very rear when bathroom is at rear of motorhome. The area for added fuel tank capacity would be directly behind the existing Transit fuel tank.