The same things that allow you to redirect controllers around the place and remap controls beyond what the baseline OS allow mean such a thing is actually quite reasonable in terms of technical ability (trying to do it on an old device without OS level stuff to play with is rather more annoying) -- "if you see this input from this device then send this input to the actual control info the game sees" is not much different if it is one button mapped to another or a prebaked sequence/rapid fire.
As far as anything I can say "download this, configure this, have fun" then I am not aware of anything but have not been properly keeping up here.
In addition to what jdbye said you do also have the option to tap off the relevant points on the controller and inject it with a arduino or something, or chain such a thing with another controller type supported by the bluetooth thing from the other day and suitably modded.