I would love to see a build on a DLP resin printer from design->build->software. Chimera: $60 DLP High-Res 3D Printer - 2
I would also like to see an episode on different ways to limit voltage... maybe rehash your ATX bench supply episode, and add a regulated 9v 3a or a 10 turn potentiometer with an output display "volt/amp" or maybe throw a DC boost converter in there to achieve 24 volts. "or could do them all and show off"
It would also be nice to see an episode on building a smart charger for multiple types of batteries/cells "could be selected by software or a dip switch maybe?"