I take a pretty large single-wall titanium mug, no handle, and use a neoprene "beer cozy" to insulate it. I believe something similar is available under the Vargo brand and probably Snow Peak and others.

Super light, the cozy keeps drinks and food warm and it doesn't burn my lips drinking my morning coffee. Being single-wall it can be used as a cookpot or kettle, if desired.

Cheers,
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--Rick