I'm fermenting in a corny right now, for the first time. I just got a gas disconnect, put some tubing on it and stuck the end in a bottle filled /13 of the way with Starsan. Presto! No need for any other hardware.
I was thinking the other night that it would be handy to turn the liquid dip tube into a thermowell and insert a temp probe into the corny in order to better monitor fermentation temps. It could be as simple as removing the poppet from the liquid post, crimping the bottom of the dip tube to be water tight and threading the probe lead through the post and down into the tube. My only thought is whether the dip tube would be a correct fit to get the right thermal transfer to the probe.