I believe you can take the controller out of the circuit by clipping one pin (According to DrJones, from this thread),
DrJones quote - "Take that driver (or look at a photo),
locate the letters "L3AD4S" written on it,
it's the pin directly above the letters "AD".
(That's the third one counted from the little dent on the chip.)Cut it with some fine cutting pliers - or something else. (Damaging the neighbour pins won't be a problem.) "
I would believe that would work and still be able to solder it back, if modes were wanted.
As far as the reverse protection diode, I have removed them when using 3AA NiMHs to gain a couple tenths of voltage limit, before the driver goes DD. 3V down to 2.7V I believe, without the diode, but you do loose reverse protection.
There's a lot of "believe" in there, which means I may be totally wrong, but I am crossing my fingers that I said it right.