Idle air control hardware

[Mike Morrin]

For my Jag V12 project, I would like to have ECU control over idle speed.
The original Bosch/Lucas EFI used a mechanical valve driven by a wax bulb
in the water rail.  Something more sophisticated seems to be in order.

I would like to know what the junk-yard options are.  In this country there
are no Detroit iron lumps in the junkyards,  are there any Japanese engines
which are suitable donors?

How much would new hardware from the US cost?

Any other suggestions?

TIA 

Mike