update--
I pulled off the NDS crankarm, in hopes of frankensteining my tange BB spindle to fit in the stock BB set. Upon removing the crankarm, the logical inner voice that I usually just ignore asked me "what d'ya think they do in the Punjab region?" So, I just re-installed the NDS crankarm and improperly wailed on the cotter to get it tight. The clearance is minimal and decidedly different from the driveside, but it is holding tight so far (prolly got ten miles on it this way). No more rubbing, thus far. I'm thinking that this is more in-tune with the spirit of the bike and its intended purpose; if it fails again, I'll take more drastic/responsible measures.

-rob