Here are links to a small kit that I favor:

The article
http://www.watertribe.com/Magazine/Y2002/M12/SteveIsaacWhenGodsPlay.aspx

The Kit
http://www.watertribe.com/Magazine/Y2002/M12/SteveIsaacMakeAHypothermiaKit.aspx

The modified em blanket
http://www.watertribe.com/Magazine/Y2002/M12/SteveIsaacModifySpaceBlanket.aspx

I've also found that a canteen cup type cooking cup and an esbit/sterno stove to heat coffee/tea/cocoa/broth for a hot beverage (boil kit) is a nice addition or consideration and some folks pointed out an MRE entree with heater would also allow for hot food/bev intake.