Well, I think I have this sorted.
Car-part.com shows a few used transmissions including a cheap one in Chicago with a bad 5th gear. I considered swapping the fifth gear because that's well documented and I happen to have a taller gear out of a diesel 02A.
In the end, though, considering cost, reliability, and my first foray into a VW transmission, we opted to import a rebuilt 02B EWB from Europe.
My understanding is that they're getting rare, even over there.