I'm going down this route now as I find flash band heavy! and i've found a site that supplies allsorts, noise damping and noise suppression combined with thermal insulation. Not cheap though it's going to cost 300+ to do it but should be toasty and quite without the huge weight T:
RAAMmat sound deadener worked a treat for me - http://t545.blogspot.com/2010/10/new-floor.html. Topped off with EZ Cool and space blanket in the panel spaces and it seems to be a great solution. Its not cheap (nearly 400 quid) but for my needs i think it was worth it.