And--this is a miracle to behold!--the bearing is both a standard and common part. "This bearing is used a lot in tractors," he commented. He drove it out and handed it to me; he'd pulled one of the seals out to get a gander at the inside, and the balls were rusted. (That certainly explains the "rocks and glass" stuff, and the reluctance to turn that fried the belts.) He even looked it up on-line at a nearby store--Tractor Supply--and gave me directions to get there. Price: about $9 with tax.
It's also looking like a complete repair will require a new tub seal (about $64, shipped) so that's not happening this month, but I can put it all together and it'll be usable, at least, until I can get the tub seal. It took the washer several years to get into this state; it should be usable a few times a week for the next month or so, until I can get the other part I need and throw it in. As a bonus, since all the hard work has been done, disassembling it next time should be a lot easier. (And faster, since I'll already know how to do it.)
So now I get to put the bearing in the freezer so it'll go into the housing more easily, and then I can start reassembling the thing. Whee!
(I'll take pics and post them later...if I remember.)