Is it possible to switch the driving games, Pole Position for example, to respond to the player 2 controller instead of the player 1 side of the controller?
Yes (
mameFAQ #h3 IIRC, but mame.net is down ATM). Even though the FAQ only mentions "keys", the differences between "keys", "buttons", joysticks and mouse axes are that mouse need to be moved/spun a good distance but not too fast, joystick needs to be moved far enough, and keys and buttons need to be pressed long enough.
If the page still isn't up: tab, select either "Input (general)" or "Input (this game)" (by pressing enter usually), go to game input, select (aka "enter"), press/move the input you want to map to, wait a sec. (don't press twice unless you want it to be NOT that key; after first input, press enter and other input if you want another key that does the same thing) Repeat. Ta-da!
HOWEVER, official mame is not set up to differentiate between different mice axis. (well, official mame in win9x & ME is not completely set up, while in winXP & 2K it is not at all, period.) All mice's inputs are combined by windows, and all control player 1 by mame's default. So your second "mouse" steering wheel defaults to play as player 1, no problem. The problem, if any, would be getting the first mouse to NOT control player 1 at the same time.
And if you get your steering wheel hooked up as a mouse, could you post how you did it?
(Once I get MameAnalog+ up to date, you could use that to get multiple mice.)