@steven
I recommend finding a local production house for PCB production. You can also export for production threw fritzing. There are a ton choice’s for PCB manufacturer’s. Now for a custom mouse shell. You’ll need to find someone that can machine a mold from your drawing and or design files. From there you’ll need to find someone that does plastic injection molding. Given the brevity of this question, following a project of this nature threw from start to finish is far more then a 10,000dollar project USD. And if you can get production ready within that price range, you’re simply baller, no questions. I recomend this same post real quick over@ the eevblog. That is a super active discussion forum pertaining to the engineering side of a product from start to finish. A good resource nonetheless.
Good Luck