If I were you I'd nip down to a hardware store and peruse the switches; I modded my Megadrive with a rocker switch I got off eBay. Unfortunately, it was about twice the size I thought it was gonna be... But yeah, if you find a small light gray rocker I think that would look sweet.
Also, remove the switch first to have a look at it before you go buy a new one, you'll need to know how many connectors are on the inside. It's probably single pole double throw, but you need to make sure.