Wheel bearings aren't really rocket science! With a little creative machining, I'll bet some of these oddball bearings could be replaced with a similar, but slightly different dimension bearing. There's nothing particularly difficult about machining an adapter bushing to make a bearing cone center on a spindle, or to make a slightly undersize cup fit a hub.

If someone wants to work with me on the ones that are really scarce, I'll bet I can come up with a suitable substitute.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!