WHEW!
Took the car in to the local Goodyear shop today. They are the ones that said they had a "kit" that could remove them.
Turns out that "kit" is just a drawer full of case-hardened steel sockets.
Finally found the one that fit just right, and with some slight encouragement (and a 5 lb. sledge), got the socket jammed on there, and removed them with an air wrench.
Man am I glad that's over with. Otherwise, I don't know what I would have done. I think the only other choices were very destructive, such as drilling them out, splitting the nut (good luck on that one), or using a torch (which means replace the rims when you're done).
I
HIGHLY recommend either getting an extra key for your wheels, or buying a brand that you know will still be around in a few years. Better yet, buy a brand that has a key that amounts to basically a big Allen wrench for a key.