There is a manual throttle body available for 1G-FE vvti motors. They can be found on GXE10 Altezzas and late (vvti 1G) GX100s, only on the non-TRC variants. They have stepper motor idle control, so will not be compatible with an IS200 ECU.
E-throttle on the left, Mechanical on the right (click for full size):
This is an option for running aftermarket ecus which don’t support drive-by-wire. They can be found easily and cheaply on yahoo japan, but you will need a forwarding service or local agent to send it to you.
There’s been talk about this option on forums and youtube comments for years without solid information, so I hope this clears things up a bit.
GXE10 機械式スロットルボディ (GXE10 Mechanical Throttle Body) [22210-70420]