Does anyone recall the old Marmot Sherpa shirt? It was a bit like their DriClime tops but featured extra insulation quilted onto the chest area, the idea being that a backpack would provide plenty of additional warmth for the back. The overall level of insulation was much less than a typical down jacket or other garment for wearing around camp, being intended for wear whilst actually walking.
I never managed to get hold of one - they don't seem to have been produced for very long - but it struck me as a good idea and certainly one very much in keeping with lightweight hiking. Are any manufacturers currently producing similar tops? and do any of you have experience with, and thoughts on, this sort of area-specific insulation?