[jimmydean]

Just think of a raised bed most guys (like I will be doing) do to cover the notch in the back and have a solid floor without the hump.

You could raise the whole floor of the Burb about 6" (or whatever would clear the back of the sub with a little room) then you mount the subs in the floor either in the corners, or along the side so you don't cover/hit them with stuff. You could do it smack in the middle to, just make sure you do some sort of a screen or grill.

My brother and I built an '88 SS truck that had 4 10" Nakamichi subs mounted under the truck in band pass enclosures with the ports running up into the floor behind the seat. It won IASCA 100W pro class Nats and was the first of its kind. Not the most practical, but it was cool as hell. Boxes only hung 1" below the frame (truck was a hot rod, not low and slow).

You can make it out of wood, then fiberglass it to make it weather resistant.

All I use on my builds are a table saw, jig saw, Dremel, and drill.