Thanks to the magic of ebay, I've now acquired a replacement Brain, this one with an accompanying Pinky. I paid almost $300 for it. A solo Brain just went for $50 (the reserve) plus $30 shipping, so I overpaid, but I wasn't sure if a brain would come up for sale again, and I think the second one got hurt by having a reserve price, which stopped a bidding war, and also by not mentioning pinky, so it was hard for it to show up in searches.
In any case, I've got my replacement brain. woohoo!