The bed thing?????
I dunno......maybe the bedliner stuff will work if you make all the dam stuff, and do several coats........but it's not the way I would do it.
Back in the late 60's and early 70's when the "Van Craze" was in full swing we did a LOT of custom vans.
Usually we just put down a thin layer of sound deadening material (and sometimes not) and then screwed plywood to the floor and then covered it with carpet.
If you use the kind of plywood they use for house floors it is kinda tongue and grove that locks together at the seams, and it is often treated so the moisture thing is taken care of.
Then you roll the carpet over the edges or use a threshold strip just like the stairs in a house.
This also gives you some sort of base for mounting (screws/bolts) other goodies to.
You could even lay in luan wood strips in the valleys (glue them) the some cement board, and lay tile on the top. That'll get heavy but you could be very creative with it.
OR>>>>>>>lay in the luan strips, and then just use some of this new floating hardwood floor products that are out now.
The possibilities ARE ENDLESS!
A lot of us went the Van route because we had kids and Wives, and could not afford to go the horsepower route.
It gave us a way to play seudo hot rodder/project builder..PLUS haul the kids and the Wife!
The bonus was you had someplace to sleep it off after the partY!!!!!!!!!!!
nO DRINKY AND DRIVY!!!!!!!!!!