I've used wondercups before, they're a bit fiddly to press in but seem to work fine.
Other alternative would be to fit some cheap BMX three piece cranks with an american BB, you can get som bargains if you're prepared to wait.
Referring to my previous reply to "why do you ride retro" you've only got to look at this to see why... Cool as fook, I can imagine riding that on Brighton front mid summer.
