Lets get some things ticked off:
- Friction shifting, check
- Narrow stance cranks, check
- 2 or 3 spacers on the right hand side, check
- Single chainring, check
(That's the context.)
- Are there cassettes which can be disassembled completely and reordered?
- If so, what type/what manufacturer/what time period/what product line?
- If you take out cogs 6, 5, 3 from a 7spd cassette, is there a derailer capable of handling that range?
... Anything I haven't thought of?
edit: I just thought of something else... The spacers may not be such an easy part to get hold of. The spacing is all completely different. Would 4 7spd cogs + 3 of what might be called '7 to 8spd' spacers all fit together nicely on a 7spd freehub? This is what I'm not sure of.