@trippy86
I'm an engineer too :) I couldn't resist the urge to build it myself, but of course it helps if you're familiar with woordworks.
If I should have changed one thing, I would have routed out some of the wood from the inside of the boards, e.g. in hexagon shapes to save weight but still keep some stiffness - this arcade weighs quite a bit :)
Wiring is not that complex with a RPi, mostly consisting of signal wires and ground wires from the iPac to the buttons. The illuminated ones need a few more but that's it. Keeping wires tidy helps the overview, but there's countless videos on YouTube - check them out.
My screen size is a 16" 5:4 and I think it's a pretty good size, and since many games run 4:3 there's only black borders in vertical arcade games. Just look at getting one that's as fast as possible (less input lag/response time), maybe a modern one with a gaming mode.