Here's a post where someone did that:
http://www.skoolie.net/forum/viewtopic.php?t=718
Professional looking job.
I want storage underneath too, but I don't want to lose that ground clearance. I go to Bluegrass Festivals, and sometimes the terrain is pretty interesting. I'd like to build some boxes underneath that are flush with the bottom of the body. Nothing fancy, just a place to haul firewood/tarps, bottled water, etc.