In 2008 I decided to "mod" an IBM Model M keyboard by repainting it. Here are some blurry and lazily cropped photos of the process.
If you look closely you can see the name of my old highschool branded into the plastic (top right). I'm not even sure how I got it - I think it was through a friends brother (I had graduated a couple years earlier) when they were cleaning out some computer lab and people could just take what they wanted. I guess they were finally swapping out PS/2 for USB peripherals.
First, taking the keys off. These keyboards actually have a second layer of keycaps (where the letters are printed) that snap into place. This would easily let you rearrange the letters for different layouts. I had something else in mind though...
A decade of accumulated grime, give or take (the keyboard was manufactured in 1993 and it had probably been in storage for a couple of years). Vacuuming wasn't enough, there had also been some liquid spill (soda or body fluids? who knows?). I couldn't take it apart any further and I wasn't sure how the switches would react to water, so I couldn't soak it. Instead, I carefully cleaned out the bottom plane with cotton swabs.
The whole thing dismantled.
Cleaning the keys.
Spray-painted the shell (medium-gloss, I think). I first sanded the schools name off, leaving a faint depression that's not visible in these photos.
Painted the keys. Wow, brown on brown? That sure was an appealing color scheme. And the convenience of entirely blank keys! I was already touch-typing Dvorak anyway, but still...
The finished product. The paint didn't stick to the plastic very well and soon started falling off. Also I'm not sure how healthy the paint was for skin contact. Anyway, I used it for a couple of months but soon switched to a Kinesis Advantage.