@Ben_R do you by any chance have the part number for the pedal position sensor ?I did this mod to my vvt-i a few years ago. I made my own adaptor and use a Bosch unit from a Porsche.
Bosch Throttle Body (0280750474)
Porsche O-Ring Gasket (99711031900)
Lexus SC430 DBW Pedal (78010-24010)