Don't know about the IM (available only as a turnkey for the last several years) but the Beck body and frame are bonded together at the factory. The car is also painted and the full interior installed there. Restoring one would not require separating body and frame, and in fact it might not even be possible. I'm sure you could obtain replacement interior bits through Special Edition, but there not normally sold separately.
The build process for the Beck is pretty much this:
- Install engine and transaxle
- Hook up wires and fuel to engine
- Hook up shift coupler
- Install front spindles and brakes
- Install lights (car is already fully wired)
- Add all fluids
- Bleed brakes
- Hook up heater boxes if so equipped
- Hook up emergency brake
- Install steering wheel and shift knob
- Install battery
- Add miscellaneous owner-specified trim thingies
- Road test
- Grin a lot
That's not as much of a simplification as you might think. With the exception of a few trim items, a crew of folks built my car at Carlisle '06 in a total of 16 hours. As for finding an older one in need of restoration, I don't think they've been around long enough. The few used ones are only a couple of years old and in pretty good shape if they haven't been abused.