You can run Paul's controller up to 144 volts anything beyond that it will not work. the FETS are only rated at 200 volts...You might try surpluscenter.com in Lincoln, Nebraska. You might contact them, they don't have them in their online catalog but they used to sell aircraft starter/generators and engine driven welder conversions.
I am currently running one in a 83 subaru station wagon. I sucessfully ran it using a Paul Holmes PWM controller on 104 volts to the armature and sepex field at 24volts. I fried the controller when I added batteries to bring the voltage up to 180. Until I get a new controller built, I am running it on 8 big car batteries at 24 volts using only a on/off contactor and using the clutch and 5 speed transmission. It actually drives quite successfully in this simple mode. The motor is enclosed in a sheet metal cover and cooled with an electric radiator fan.