These look awesome. I imagine a metal badge in the top corner like a model F or M is out of the cards for the 68 key? On either board, if you're going to have a metal badge, you might want to make the dimensions so that they fit OG or reproduction IBM badges, because I imagine people will want to be able to swap those in.
I agree that none of those switches are particularly appealing. Kits without switches would be ideal, PCBs without any hot swap sockets would be better, but I know that may not be mass market enough.
An MX-compatible SSK sounds like (oddly appealing) heresy to me.