I have thought about getting this water bottle, it is Stainless and can be heated in the fire. I like the Sigg canteen, but they are Aluminum with a coating and cannot be used for melting snow (direct heat) It is the only one I have seen that also has a Stainless Steel top.
http://www.wiggys.com/moreinfo.cfm?Product_ID=100&CFID=47440&CFTOKEN=86575741