1. Look into a gamepad hack and an Oscar Controls USB optical interface (pre-done mouse hack).
Another way to go, if you are sticking to MAME(tm), is to get an IPAC VE for the buttons/joystick. I love that thing, and it's an order of magnitude easier to wire than any kind of hack-it-yourself solution.
What kind of spinner are you using? If you are ordering one, see if they also sell an interface and get one shipped with it.
2. As for admin buttons, if you use an IPAC or a KeyWiz all you really need is a shift button and maybe a coin button or two. Everything else can be a combo of the shift/shazam and one of the buttons on the CP.
3. Search these boards. The topic has come up before. I did and found
JoyMonkey's list of vertical games.
Post pics of what you come up with!
Good luck.