[I'm not trying to hijack your thread Hoopie so I'll leave it at this... for now.]
Hoopie: Thank you! This helps a lot. I’m trying to decide if I want to do a Prius and a truck, or a Yaris and a VW Beetle. There’s pros and cons to both but your advice does help. But still no easy decision.
One of my main concerns is that the Beetle (in your case the Karmann Ghia which is almost identical in many dimensions) would sit too high up. But another concern was that the Prius would be too wide yet you showed it is not too wide.
BTW you said that the wheels poke put a bit and your think about adding fender flares. Nah, they look fine! I think it looks cool like that. For wheels I would look for some Prius base model steel wheels, that would look fairly period appropriate IMO, especially with chrome hubcap centers.
Edit: after reading your whole thread a few times now and in closer detail (Bill the Engineer's build thread is next to go under the microscope) it is starting to make sense to me. You're removing the bottom few inches of the Ghia body, lower threshold for the doors (rocker panels?), to make it fit the width of the Prius's inner rocker panels sections - but it will also help to keep the Ghia body low enough for the right stance. Then you'll need to weld it all up including an outer skin to make new rocker panels (right?). That's a lot of cutting and welding. Just a lot more work, not terribly hard to do though if you have the proper welder for thin sheet metal.
Freebeard: yes the Prius I'm looking at is a driver so I'm told, it has the spare tire on where the body is wrecked, maybe because the rear quarter panel was pushed into the wheel, but it doesn't look bad. I don't know until I look at it on Sunday. And yes an old C10 chevy would be pretty easy to drop on top and is what I would look for, 50s or 60 era. I restored a '83 K10 a few years ago so I know a little about them:
http://dannix.net/lib/truck/k10 only problem was it got 15mpg (not bad actually for an old v8 4x4), top speed was 65, no a/c, etc.