I'll take a set of the boards if you decide to sell them bare but include the ICs. I'm a pretty good solderer so it shouldn't be an issue.

I'm willing to sell my main boards as well, but it would be costly to get them made with all the components installed. I would be more than happy to sell them blank provided the buyer can solder the components. I would even probably be happy to sell them with just the 3QFN chips soldered which are ...

Get an old IDE HDD ribbon cable and use that, also 26AWG should work fine for this.

Yes that's what I used because it's what I had on hand but the actual size of the original buttons on the case is the 10.8mm.

I ordered one just now but it was the white one, I'll see how much it weighs and figure out shipping. If you don't want the white one I'll just keep it for myself for a future project like you're planning to do and I can then order the black one if shipping isn't a deal breaker.

I can send it to you but if you could get the actual weight of it I can figure out the cost to send it to you. Anything over 13 ounces is expensive as hell.

Using my calipers gives me 10.8mm .

I'm actually working on a project using an atmega2560 with 2 other people that is way more advanced in complicity and code, and I can ask them for a little help on the code end to see if they can come up with something.

Cool I'll handle the schematic and maybe you can edit the code. I was wondering how many more pins are available for buttons? Maybe add another 6 like X,Y,L1,L2,R1,R2 or will that exceed the available pins?

If once it's programmed using USB and if it can be reprogrammed using USB it will be a piece of cake but if not we will have to use the ISP pins and an external programmer.