Nice project.
Manufacturers are doing this more and more with "Eco" buttons that smooth/calm throttle inputs (among other things).
There was a similar mod done by Julian Edgar (Autospeed) and others for the 1st generation Honda Insight which was intended to smooth out throttle transitions in order to keep from accidentally kicking the engine out of lean burn mode. In that application, a capacitor was used to "buffer" the throttle signal:
http://ecomodder.com/forum/showthrea...tor-25641.html