First, congrats on taking on this project. It's pretty cool.
1. Why metal and not wood/fiber glass? Just curious since metal hurts worse in an accident or as an arm rest.
2. What about covering it? I presume you didn't want customers running around with an open frame. If so, did you account for lowering the center console enough to accommodate a build up of a foam arm rest and a door to access the insides.
3. Just a suggestion, but since you did use steal, if it were me, on the non-computer versions I would build a safe into it. When I play racquetball, I don't like leaving my stuff in the locker, but at the same time I feel it's more secure than any place in my car. I've been thinking for quite a while about welding up a lockbox somewhere in the car and maybe hiding it behind a panel or carpet or something. Then I could lock my wallet and stuff in there. It would be a cool feature and not much more cost, I think.
4. You didn't show the shorter version in the car, but the tall one looks like it comes too far forward on the e-brake. Does it?
5. Details are everything. I'd like to see a covered, finished version.
Keep up the good work.