Davis craig pump may be controlable via a H bridge or a PWM output using the volvo fan controller in the link
http://www.mrm-racing.se/forum/forum/public-forums/autronic-support-software-downloads/autronic-support-forum/828-pwm-control-of-electric-water-pump/page2
Suggest we could probably use GPPWM to link pump speed to temperature and TPS load?