Well, I've confirmed that the pedals are the 4" block style, and that there aren't any in the bins at the local bike co-ops. Looking at prices on Ebay seems to show that I'd be buying a nicer set of pedals for anywhere from 1/3rd to 3/4s of the price I paid for the bike. I found several nice French rat trap pedal sets still attached to their cottered cranks in some bins, so I might clean those up instead. I think I'll post an ISO in the classic ISO thread for a spindle and see what happens.