My current project is my keyspan remote control. It has replaced my XKEYS keypad. I use the keyspan because it it programable for almost any software program/keystrokes. I wanted to mount it somewhere that is easily accessible and does not take up a lot of space.
I didn't want to mess with my current cupholder because the finish makes the piece rather expensive. So I purchased an extra cupholder with trim piece from a Mazda6club member from an 04 mazda6. The finish does not match but I don't care about that at the moment. I will have to match it later anyway.
I dismantled the receiver so I had just the bare circuit board with no housing. That made it roughly as tall as the remote itself.
Next I wired the 5V from the USB directly to the remotes battery terminals. The remote will be fixed in place and I don't want to have to change the batteries all the time. Although the remote takes 2x3V lithiums, 5V from the USB was plenty of voltage to power it.
For the cup holder, I removed the plastic cover to cupholder to reduce thickness. When it opens you will see why. There was only two screws and a few clips holding it on.
Next I hot-glued the remote and receiver in place. When I tried to open the cupholder it hit the side of the trim. I knew this would happen. Next, I used a scoring razor blade to shave off the needed space on the trim panel. When I was finished you could see it opens.
I still have to do some fiberglass work to make it look factory. I will post that whole process up later. For now here are my pics.