This Is a Job For....
STEVET!
Here's what I'm wondering, and I think stevet could help more than anyone else with the question:
First, what is the part number for the motor? And,
Second, does it cross over to anything Hobart? Remember that KitchenAid began as Hobart's "residential" line, based on their commercial stuff, and that the farther back you go, the more parts-sharing there was between the two brands.
So, if stevet could chime in here, I think it would be helpful. Even if we don't find that Hobart repair centers have an off-the-shelf replacement, it might be that we find that something of Hobart's used the same motor, and we could find a rebuildable core that way.