Thinkpad Retrofit: Keyboard Part 2 - More Questions Than Answers

A number of people have volunteered a lot of information: this is mostly me collecting facts in one place so I'll lose track of less of it.

There's a problem here, and I'm not quite sure how to express it: there's a barrier to entry somewhere between "where do I start?" and "what does this mean?" I have a keyboard. I know I'm probably going to have to decode the keyboard matrix and connect it to a ATmega32u4 (probably on a Teensy 2.0). But the people who write these pages have already done so and understand things, use terms, which I don't get yet. What's the entry point for all of this? The "starting from Zero" tutorial?

Finding an Teensy 2.0 in Toronto turns out to be trickier than you'd think: my usual computer suspects (Canada Computers, New Egg) don't have it. Amazon Canada only has it from secondary sellers. Creatron only has the 3.2. Sayal - to my considerable surprise - doesn't seem to have any of them. The Adafruit version listed above would be great, but buying from American sellers can be problematic on this side of the border.