Just an idea - if you can get an LED to run off a lithium battery and fit in a Char-G, then why not the little speaker and chip that plays music out of those annoying greeting cards, that run off a lithium battery? If you can find a card that plays "Dixie" you can have your own Dukes of Hazzard bit! I'm assuming the mod for this would be the same for those light mods that allow you to switch on LEDs from your controller (light brakes when you stop, turn signals when you turn, etc) but modding a booster button could work too, or even assign 1 of the 4 bands from a 4-band controller...i'm just throwing ideas out there!
of course there is that OEM that makes motor noises that you can thankfuly turn off from the controller...but now you can have any tune you want (from hallmark that is)!
Here is the article that gave me the inspiration
Threaded Mode