Gerdo, here is the basic construction method for the 1/4 Nelson Stacker. Using a HF 40" x 48" trailer, I removed all but the long spring from the suspension. Then a 36", 1 3/8"hollowcore door was cut shorter to 6 ft long, and a stiffener inserted within the cut end, glued and clamped. Next, two 6 ft 2x4s were cut down to 1 3/8 x 2" and glued and screwed to each side of the door, providing a total size of 40" x 72". Carriage bolts were then used to secure edges of door to HF frame rails. Now the teardrop floor was all done except for the coat of roofing pitch on the bottom.
The 1/4" sides were then glued and screwed to the solid members of the door. (Not an ideal construction practice, but works for me). Bandsawn pine members 1 1/2" wide were glued and screwed to the upper edges of the side walls and roof trusses fastened to them, screwed from the outside. The hatch lid bows were made from 1/2" baltic birch and hatch and roof covered with 1/8" lauan plywood........that's it, except for a 1/4" worktop in the galley and 1/8" sliding doors on simple galley cabinet. Total weight without all camping stuff, 245lbs. It seems to track down the interstate at 65 mph just fine but hasn't been wind-tested here in So Calif. Total build time for above stated work, about a week and a half.
This is only a one-man teardrop, and being only 5' 9", it's 6 ft length works fine, with toes just about touching the hatch lid when closed.
Good luck............Roly