Third one is definitely not mechanical. It's rubber dome. It's not a bad board though. It's a true rubber dome, not membrane, and uses individual little rubber cups. Similar to the minitouch plus. Cept the domes are much softer. I'm using it as a spare right now on one of my machines because it doesn't feel awful and requires a lot less power than a minitouch. It doesn't reset like minitouches do on usb hubs.
That's also the version that had the function key row cut off as a prop, and used to kill someone in Gattaca. lol
omg just looked at the price. $145 is ridiculous. Think I got mine for like $25.
The second one however looks very interesting. I've never seen that board before, and the seller reports that it has a "click sound" not that it's a clicky keyboard. It also has a really interesting name, "The Count", a keyboard for vampires? lol It also has a layout very similar to the minitouch. I would be surprised if it's also a Qtronix QX-083, but perhaps it's an early version of that board? I think more likely the seller just listed it like that because he has the other one, and it doesn't likely have a number on it. The layout is really interesting, what's with the extra +- keys?? Also notice the control key is in the proper position. I wouldn't be surprised if it was a monterey, and is a minitouch early prototype version. The one thing that concerns me is that it doesn't seem to have a function key layer.
*edit* I bought the second one. That board is really rare, so figured it was worth a shot.
I noticed he did list the other qtronix board as having a click sound too, which it doesn't, but perhaps there's some confusion going on between them.
