nah! 12v won't do any harm, least not roasting your spuds !

i would be interested in the wattage or amp draw. if the bike can handle a couple of extra spots at 55watts each i 'm gessing a seat cover fashioned as a waistcoat should not be a problem.

last year maplins had heated jackets [reasonably priced] the batterys.... oh here, check it yourself http://www.maplin.co.uk/self-heating...aistcoat-47715 i never had the bottle to get my self one! i cannot see why it would be a big deal to modify using the appropiate resistors and connect it to the bike, maplins also sell neat connectors too

keep us imformed!