Mostly just trial and error… Lots of searching the web, lots of reading… The Arduino Forums are an amazing resource so much brainpower available to be tapped 
I had an advantage of already knowing how to code in C, but it’s not that tough to pick up enough to do what you wanna do..
Ok so I’m thinking Ill order a run of about 20 of these boards and actually build up two of them (for testing). I think the soldering would be easy (even for a beginner) as everything is through hole and you don’t HAVE to solder all the pins for the arduino interface section. If everything goes well Id like to just sell the bare boards and will prob sell the two I build up. I’m trying to avoid soldering these to completion before selling as I think this is a great DIY project but I may depending on interest. My biggest obstacle at this point will be optimizing the code (I have a bunch of sketches for the individual controls that I need to make into 1).
As this is designed for the user to build up and purchase their own arduino mega, would people want to buy MEGA boards with the USB MIDI firmware already flashed? This would mean you would have to get a ICSP cable to reprogram the board as you cannot flash over USB once the MocoLUFA firmware is uploaded (take away the serial interface that Arduino IDE uses).
For the sake of your wallet… DO NOT BUY 20 BOARDS out of the gate!!! D O N O T!!!
The last thing you want to happen to to spend a couple hundred dollars only to find out the board has an error
Get a small run of one or two boards, just to make sure the layout, traces, etc are all going to work…
That way you can make tweaks to the board and you’re only out the cost of 2, not the cost of 20…
Re: code… I’ll be more than willing and happy to help test things out for you… I don’t have a mega, but I can figure out a way to test the board…
While u do raise a good point the setup fees alone with a board this size make a 2 board run very expensize. Ive had pretty good luck on my other designs so I feel fairly confident. I would love some links to any services youd reccomend. Thx
What’s the dimensions of the board? It may be an idea to try:
It’s $5 per square inch shipped… No setup fee’s no nuttin.. 3 copies of your board too, in any colour you want (as long as you want purple)…
that looks just the job; would save me loads of wire/solder work if i can work out how to create a pcb for my diy controller.
got any recommendations for where to start? I should be using eagle right?
Would you be willing to send some to the UK?
I would definitely buy if so.
Yeah shipping to UK shouldnt be a problem. The dorkbot service is great! Ive used it once for some small boards and they were very good quality. This board is roughly 4x5" so that would equate to about 100/3 boards= 33ish a board? Hmmm not TOO bad.