This sounds pretty awesome to me, actually! I think this is exactly what I was looking for. In my case, I want to have a dual screen cab (a modified PlayChoice-10/ Punch-Out) and have the game selection be on the top screen, while the game plays on the bottom.
For some games, I want to use 2 screens (Punch-Out). For some games I want to only use the top, veritical screen (DK) and for some, only the bottom, horizontal screen (Vs. SMB).
Any idea if this would be able to launch (and close) 2 programs at the same time? For PC10 games, I want to have the instructions on the top screen with and NES emu running on the bottom, since PC10 games play better via an NES emu rather than mame, but I want to replicate the arcade experience since PC10 was my favorite arcade game.