I agree with this up to the point where you won't have enough inputs to wire everything to the UltraStik 360: I bought two UltraStik 360s myself and the plan I have for them is to use the P1 Start button as a Shift key for the other 7 buttons. This can be done on the software side of things, although I haven't gotten to that point yet. So, say I wanted to press Escape but haven't wired a button to act as the Escape key: I hold P1 Start and press button, say, 6 which the software will interpret as "Escape".

This works, as there aren't any arcade games which require using the start button in conjunction with any other button in the game.

I had discovered this method after making a big order (which incidentally included an IPAC2), and now I may not even need the IPAC.