Buried within the Debian download directories (which can't currently be accessed because whoever is doing maintenance doesn't understand what a mirror is), is an
unofficial live ISO with cinnamon and the non-free firmware - basically the two reasons for wanting Mint.
I hacked with URLs to find 9.5/Stretch (stable) on a mirror - wanted to try 10/Buster (testing) but looks like the weekly releases are only on the offline official servers - though I still need to find a spare USB drive to put it on.