https://www.ebay.com/itm/IBM-Model-F-107-Keyboard-for-4704-Banking-System-Genuine-Unmodified-F107/284236884011This one's got many days left and it's going for six hundo. I don't remember what I paid for mine, working albeit unrestored with a preinstalled xwhatsit, but it wasn't substantially more than what this bad lad's at with a few days left. He's also got one that we could probably rebuild for $679. And I thought I overpaid!
For the right buyer, this is a great deal. For the wrong buyer, this is outrageous.
Here's why I'm saying it's a great find though:
This is literally the best keyboard ever made. It does not get better than this. This thing has the best build quality money can buy, and arguably the second best, or first best, switch technology. It's got what is functionally a modern full sized layout. These are only ever going to get rarer, and at some point they basically won't ever be available for love or money, and it's just going to be us nerds with em and they won't hit the internet until we die.
