As you start driving off, the vehicle automatically locks itself when moving above a certain speed.

Girlfriends daughter is driving me crazy asking me to lock the doors after driving off. She isn't wrong, living in South-Africa it is probably a good idea to lock the doors. It'll also be a fun little project.

Initial thoughts:
Design a little module that intercepts the vehicle speed signal and outputs a command to lock the doors.
Vehicle speed can be intercepted before the EAS Controller (Yellow wire right? 12V square wave I assume?)
Commanding the doors to lock might be a bit more complicated. I'm guessing something along the lines of making the BECM think that the user has pushed down the sill switch. Looking at RAVE (not in detail yet) it seems to be the Green/Red wire between either the Left or Right Door Outstation and it's corresponding Door Actuator will be a good starting point.

Anyone else have any further input? This idea is in it's infancy, but I can't see it being too difficult to do. Actually, has it been done? I haven't searched to see if anyone has attempted it yet!

Any pitfalls I've missed in my eagerness?