Spindle length is dependent on the crank you use. There's a resource on Sheldon's sight (click articles, look for one on crank spindle length).

You can also find old French threaded, Japanese made bottom bracket cups. These have a thicker wall and will work with the more standard "3" series spindles. Sugino, Sake, and Shimano all made these cups; emphaisis on made... you'll have to troll ebuy, but they do show up.