i see a lot of those older conversion vans at our local pick and pull yards. ive laid down on a few of them checking them out, but none of them were long enough to sleep on front to back for me and im too tall for side to side sleeping.
not sure about your area, but the vans at our yards dont get picked apart at near the rate the civics and toyota trucks do, so it might be worth the trip to a salvage yard and see what you can find. like scotty said, be on the lookout for other rare van scores like popout windows, conversion van windows, larger swaybars, limited slips, etc. list goes on and on. ive even found really cool crap like a 7x7 awning and only got charged 20 or so bucks for it. that same campervan had a good 30' of piano hinge in it too that they sold me for 5 bucks. cant go wrong at salvage yards