I find the perfect heat powerflight is pretty hot - 3 cords, all under 15 amps. Smaller vac motors, so 50 foot runs need extra dry passes. Only 4 cords for the Worriers, but it's not that complicated.You're not going to find truckmount-like heat on any portable that I know of short of running multiple heaters and 7 cords like Willy does.
Otherwise, you can do this for heat:
http://www.***************/kleenrite-heatrite-line-heater-carpet-cleaners-p-3476.html
Hint - pull the 190 degree stock Selco disc thermostats and put in 220 degree ones.