I have an extra one of the throttle pulley setups in good condition and the vacuum actuator with bracket. You would still need the cruise control vacuum pump and the turn signal lever with cruise switches (and vacuum and electrical switch(es) at the brake/clutch pedals) but those are all the same on the gas engine cars and probably easier to find.
Shipping for the throttle pulley/actuator parts might be expensive from the US but maybe not too bad since they are light. Let me know if you are interested and we might be able to make it work.
The cruise control throttle spools often have problems with the bushings wearing out. Tom Bryant has a method for rebuilding them. May want have those done in advance if you are going to go to the effort of getting cruise installed.