What? You thought I was some genius?
I have been looking further. Here's the owners website:
http://www.bugwing.com/. It turns out he did all the work to promote a particular religious perspective, AKA proselytize. The link to construction details at
http://www.digitalbiker.com/bugwing.htm hits a wall for me.
Here's two pictures of a front engine/rear drive trike:
I agree about the plan taper, but I'd start the pie-cut at the A-pillar instead of the B-pillar. It's narrower there and you'd only lose a little elbow room.