Check these things out:
IkEY FT-88-911-TP USB Mountable Backlit Keyboard Integrated Touchpad & Adapter
They're going for about what you would expect from some sort of refurb/used/surplus TG3 cop keyboard, but they have some additional keys, including a Windows key. They're designed for mounting, just like TG3's boards, and they seem to boast the same sort of dust and waterproofing.
iKey's specs on the switch are basically as descriptive as possible without really saying much of anything definitive about switch type:
MATERIAL: ABS Polycarbonate plastic
LIFE: Greater than 10 million cycles
TRAVEL: 0.120 in. (3.0mm)
ACTUATION FORCE: 2.20 oz +/- 0.18 oz (62.39g +/- 5g)
FEEDBACK: Tactile with mechanical snap
A mere 10 million cycles maybe suggests regular rubber domes? Does anybody happen to know for sure? I'm pretty sure "ABS Polycarbonate" doesn't even make sense, as they're separate types of plastic, unless maybe one is shot into the other for some reason?
Interestingly, the
product page also seems to suggest that a mere cable swap can enable this board to work through either two ps/2 connectors, or a usb connector.