Someone told me to submit this to the Hackaday Prize 2016. I'm over 18 now, so I guess I can, and I did. Here goes!
I have been doing work on and off with this, most of the issue residing with my CNC machine more than with this project.
Here's a list of new developments:

- We no longer need to search for old DMG cases to dismantle and put new components in, Kitsch-Bent makes custom ones that are identical to the originals! (almost) Unfortunately, new holes will still have to be drilled for at least the X and Y buttons, and L/R shoulder buttons are still a work in progress.

- Those 7.5mm buttons look just about perfect!

- The software should be working now, it's just a matter of fixing tri-state logic issues with some resistors. The circuit board has all that built in, so once it's cut, that should be fixed.

That's all for now, I think. Maybe I'll have a picture of the Real Deal(tm) ready soon.