[brucepick]

Including tapering sides for the false trunk lid is probably a good idea. aerohead suggested this somewhere- I believe it was in a pm.

I'd use panels attached to the C-pillars, hopefully tapering inward along the template line. The coupe's C-pillars do taper in so one might be able to just continue that line.

I do believe you'd end up with something very close to the Gen 2 Insight back end, by that method. Insight 2's dark glass rear vertical panel is noticeably narrower than Prius's, if you get a chance to see one.