Well, I'm kind of new to MM themes and all that stuff, but I've figured it out, and am starting off by skinning the Dual Mount SD Widget found in the market, it costs a dollar..
I can customize it for you if you'd like, just tell me what you want it to look like.
You will need to move the apk file 'com.protocol.x.USB.apk' to /system/app/ first using Root Explorer. Then just apply the .zip using metamorph, and viola.
My Custom Plain One
[Pictures aren't very good quality]