SUMMARY
OK, we can go with what will actually be less of a kammback and more of a removable boattail.
So it will be functional like this:
And much more aerodynamic than this:
http://priuschat.com/forums/attachme...r-img_2810.jpg
But, while removable, will be a boattail like this:
http://forum.ecomodder.com/attachmen...p;d=1202612003
The upper portion of the boattail could be opaque since I don't think its legal to have something without proper lights or safety markings go past your rear bumper by more than 2 feet... this would plug-in much like any trailer would and require a simple wiring harness.
The body could be made without any compound curves of some flat sheet, but ideally should be molded, and reinforced internally with hat sections.
(I didn't know what a hat section was, so I looked it up, as follows)
http://www.indiamart.com/frontlinero...n_10529477.jpg
Lights can be added in the rear, like the Aerocivic, but stylized to match the lines of the prius.
This "Removable Boattail" design could be adapted to any number of different cars, and kept under 100 pounds.
Tomorrow I'll to to the local raw metals wholesaler and pick up a small stick of aluminum box tubing to form the portion of the Removable Boattail that inserts into the hitch. Once that's bent and drilled I can get out the cardboard and start making a mess!
"Opportunities" yet to figure out:
1. How will the removable boattail attach to the body(besides the hitch)? Will it use a foam gasket? Is it important to attach at all, or should it be spaced apart from the upper trailing edge of the body by 1/2"?
2. How to open the trunk without removing the boattail? An extra lift-lid attached to the spoiler?
3. How to open the boattail itself for cargo access and light weight?
4. How to maintain driver visibility?
5. Bracing layout for "crumple zone" safety provision.
6. Anyone else's suggestions or ideas, I'm sure I'm overlooking something important.
Thanks all for your help!!!