Not to pick on ya, but how the heck do you lose a thermos? I think I've still got one that I had in high school, and I know my dad still has a super-old one from 30+ years ago with a glass liner.

SIGG bottles have a 'biner cleat built right into the stopper so you can clip 'em to stuff. The 500ml REI vacuum bottle fits (slightly wedged) in a water bottle cage. It's a big honking tube of metal and makes a ton of noise if you drop it.