
FWIW just saw your post today
This is copied from my post on the minimania forum Aug 10,2012 with some additions.
Here's what I built. 2 1/2 sq steel tube bolted as shown. Threaded rod thru front subframe mount holes (4). Crossbracing from front sq tube to body where it mounts to rear of front subframe. Bolted together so I could easily take down however needs to have additional cross bracing of sq tubes. Currently have a 1 1/2 angle brace thru engine bay and securing front tubes. Cantilever position is solid with proper bracing. Welding with gussets instead of bolting would help rigidity but.
Bought sq tubing (20ft) for about $90. My brother gave me angle so maybe $120.
Dolly made from 2x6's ($20)with 5 inch plastic castors ($10each).
If I had to do over I would not build the wooden dolly but weld on 1 3/8 dia pipes to sq tube which would hold removable scaffolding castors. $12 each from eTrailer.com. They could be removed while the car is tipped up as in the photo. Install castors and tip it back to original position and can move shell around just like a dolly.
Shell can easily be tipped by one person and rested on the sq tubing as shown. Shell weight is about 300 pounds.
Works very well for me with limited space to work. Easy access to bottom of shell and wings.
Build so you can move standups to the other side and tip it onto the passenger side.