I'm thinking of using a programmable keypad as a button box, like this one ($170!). The advantage of using a programmable keypad is that it does not present itself as a controller (some games have a 3 controller limit). You just program the most frequently used keys on it, so like D for Drives names, Y for Yes, N for No etcetera. And it can be placed easily because it's small. Does anyone know a similar product which is cheaper? Perhaps a DIY Arduino project...?