Can you give some pointers on tracking these down? I found this WYSE one in a video linked below, but I can only find a couple overpriced ones on ebay.
I bought mine at a Swedish online auction site. I suspect eBay is the place, but unless you are not getting an AT converter with it I would not pay more than $20.
If you find an old Packard bell with a 1.25 unit wide escape key it is certainly a BTC board. That is how I found mine. 25sek (about 3 bucks) without an AT converter.
Just look for retro keyboards. The 1.25 unit escape key is the first thing to spot. Then make sure it is the dome-with-slider one and not a foam-and-foil (which are certainly degraded beyond use by now).
Personally I think the future of tactile keyboards is rubber domes and either light-based sensing or EC style (like topre). No friction, yet great tactility instead of the almost-linear switches like cherry MX brown.
