Have you taken your current BB out? If not then do it and pay attention to which way the cups thread out...The Swiss threaded BB's don't come up as often as French but about 1 a month does show up on da 'bay....The best option if it is Swiss is IMO the Phil unit. You can then get the BB with the correct spindle length and taper for the cranks you want to use. You could also just buy the Phil rings and use a Shimano UN72 if you can find one in the right length for your desired application. The only issue with that is you will be limited to using cranks with that taper. It's a cheaper route to go though....Got pics of the bike or have you narrowed down the year?