Just something you haven't covered yet - and I bet you have some good insight into.
That is connecting two bench-top power supplies to be used at once. For +/- voltages, more (voltage, current?) and how to do it properly. Oh, and all the "traps for young players" as you like to say. Grounding issues, mains,circuit protection.
Might be a nice follow up to the o-scope ground video you did.