The Nalgene stainless steel bottles are still available, and I have used them in a fire before. The cap is held on by a cord that slips right off. I used to be able to find them at Dick's Sporting Goods, but I know they are still on Amazon. Is it the price that is inhibiting the purchase?
I have one filled with water in my GHB, but it's too wide to nest into my Snowpeak mug and more than twice as expensive before shipping and tax. The one from eBay looks much narrower and there is a chance the neck's thread is compatible with nalgene's.