Looks like that could end up working pretty damn well with some tinkering by the time you're finished. ... I'm thinking a box type setup with unobstructed pedals and stable enough for the wheel may be the best bet.
It's a trade off between compactness and restorability vs usability. Undo a few wing nuts and pull a few bolts out and mine will collapse nearly flat to be stored away. Of course that won't be true once I mount the Hyundai bucket seat I have. But I intend to make this modular so the seat and the rest of it store separately.
A few problems with what I have so far:
- I made the platform the wheel mounts to almost 2x too big, this puts the main support post too far away from me when I sit at it, and gives me issues getting the reach to the pedals right
- The forward support stay gets in the way of the pedals
- It is way too tall; a 7'-er wouldn't adjust it as high as I have made it
- This is a mock-up of sorts and is not made very well; it has started to fall apart already
Surprisingly it is pretty stable though. If you beat on it, it will wobble a lot. But if you just use it, it is fine.
Cantilevering the wheel support from under the seat isn't a bad idea either. I might try that.
A box would be optimum.. however space just doesn't permit that.