I also though about that generic blip, that would be a much simpler idea, the problem is the system needs a way to know when to do it, this is, when downshifting...
I though about putting 2 sensors only, one in the brake and other on the clutch pedal.
The blip would happen only if both where pressed, and in a specific order, first brake and then clutch. (I'm thinking on the braking and downshift when aproaching a corner on the track)
Problem is that it would blip when stopping on a red light too... 
It could be done by checking the current speed, and only bliping when the speed is above a certain value...
Zeecue: I didn't think about the cruise control... all the hardware for synchorev do the CC as well. Nice idea! 
Also the hall sensors should be easyer to install then the simple switches I was thinking about...
btw- my car as a cable operated throttle