Perskeles! What a difference! Couple times riding to work in the morning in below 40F weather wearing these prototypes... And once riding back from work them stuffed inside the jacket. Yep. I will definitely make jacket liner, pants and socks (or insoles) too. About the controller... After spending several nights with microcontrollers, oscilloscope, soldering iron, datasheets and several glasses of wine I realised I could do it with 555 timer chip and some passive components... About 10 minutes later: PWM controlled mosfet, kinda like dimmer, capable of handling up to 18 volts / 10 amps. Overall cost (without cables and connectors but including the plastic box: $5). And here is the prototype box in the left fairing pocket of my 'wing: So what's next? Do "final" gloves, jacket liner, underpants (or perhaps chaps?) and insoles (or socks). Oh, and the controller. Two channel controller should be sufficient. And then, perhaps, some kind of wireless thermostat controlled f...