I'm bumping this back to the top to thank TsPoet for the recommendation!!!

I just used my backpack thermos on my bike this morning and it worked great! It rattles a little in my bottle cage, but nothing too annoying. I'll try bending the cage a bit and I'm sure that'll secure it. But it didn't leak even a tiny bit and it is keeping my coffee super hot!!

The packaging said it would keep liquids hot for 8 hours and cold for 12 (I think). Sounds like I've got a winner here!! Thanks, again.