...bear with me, here's what i'm planning!
I've a 126mm rear-end spaced Peugeot Athena 653 frame which i'm going to run with a modern campag groupset - 10 speed Veloce probably. I'm going to use modern 130mm spaced Ambrosio campag-alike hubs (they fit in the frame just fine!) but with a shimano freehub. I've got tons of sprockets from cannibalised 7 speed shimano cassettes and I make up my own ratios you see.
I'm then going to buy a Clarks or Miche campag compatible 10 speed cassette - I understand these can be split apart and that you get all the spacers for campag sprocket spacing. Is there any cheaper way to get a set of campag spacers?
I'm then going to use my stock of shimano sprockets on the shimano freehub but using the campag spacers. I'm not bothered about 10 speeds to be honest, so as many of these sprockets and spacers as will fit will be fine: how many would that be do you think?
If I need a narrow chain to suit the narrow 10 speed spacing, will it work on 7 speed sprockets? Am I right in thinking that 10 speed sprockets are the same width as 7 speed, its the spacing between them that differs (and the external rather than internal width of the chain)?
What else is wrong with my dubious logic ??