Canoedogs, your challenge to find a stove or heat source that fits into a vest pocket is hard to match.
You started me thinking about it so I was looking through my junk and doing some searches through the supplier's materials.

I keep running into the problem of what fuel can give you a useful amount of heat in that compact of a package especially when the package includes the burner.
I seem to keep coming back to some type of can candle or one of those miniature butane powered wonders.

At least with the candle it can be used as an accelerant for fire starting.