Since Todd is a great friend to have, I now have in my possession four or five of these keyboards. They work. I've tested one of them with my LED/Matrix piece of crap, and yes, being sealed in a bag is much more conducive to proper storage than sitting in 0% humidity for a few years.

The ultimate goal for this project is to have a 'front of house' twitter machine for the hackaspace. Now that I have a few of these keyboards, I can start experimenting with them, starting off by converting one of them to USB. I'll be using the TMK firmware and a Teensy 2.0 (since we're adding those to the Hackaday store, anyway). This means most of the work is done, I just need to design a Teensy -> keyboard matrix adapter and modify the firmware.

Here's the PCB I designed:

And the corresponding switch to pin diagram/schematic:

According to the datasheet (translated from Czech by Jaromir), here's the button mapping:

This can be verified with my matrix tester, and I'll start modifying the firmware later. Just need the boards delivered, and I can start working on the 3D printed or machined enclosure for this thing.