Hey Ross,
I currently own my own self built 3D printer and have a good amount of experience when it comes to CAD based design. I haven't made a custom mouse before, as I'm not particularly picky with what I do, but I'd certainly be willing to give it a shot. If you could link a couple base mice with the number of buttons you desire and give an adequate description of the size, shape, and placement of the buttons, number of buttons, it would be much easier to design something. I would need compensation for costs though. I've been a long time viewer so I'd love to give back however I can. If you prefer to correspond via email I will send a copy of this there as well.