Liquid nitrogen is often used for tasks requiring fast and extreme cooling of other substances. Is there a substance that can play a similar role for fast and extreme heating, yet be portable in some canister?
During my PhD I used molten lead as a way of rapidly heating samples. It has a melting point of about 330ºC and its high thermal conductivity means it very rapidly heats anything dropped into it.
In terms of portability it's probably about as portable as liquid nitrogen since you could carry it about in a (pyrex!) vacuum flash, though I never attempted this feat.
As a general rule heating things is a lot easier than cooling them down, so I'm not sure there is a real parallel for the use of liquid nitrogen.