Something easier than setting up 4 MaLa/MAME instances on my computer?

[mmmPeanutButter]

Problem:
I've got a manually-rotating monitor and two control panels (joysticks and trackball). I want the settings to match the physical setup:

Vertical/Joysticks
Vertical/Trackball
Horizontal/Joysticks
Horizontal/Trackball

I've had all sorts of crazy ideas how to do this but I think I could solve it with some USB keys. Ideally, I would like to maybe have some configuration files on the keys and then MaLa checks for the configuration files on the key and everything is set up.

Alternatively (I think it would work but might be a bit kludgey) is to set up 4 separate instances of mala/MAME on the computer (with common rom folders). And then the key could just have the appropriate shortcut so when the computer runs it starts up the shortcut on the key which calls up the right Mala/MAME instance.

Am I an idiot? Is there an easy way here that I'm just missing?