I believe that you can add inventory slots in items that typically do not have them. I have not tested it yet, but playing around I found "invisible storage" containers that can be placed pretty much anywhere on a map. These could easily be integrated into specific items. A great example would be the modded test generator, that comes "stock" with a power switch connected to it, as well as dozens of branches attached to the sides, each containing it's own power output.
I have seen, before, a plugin for the refrigerator, to make it require power to function (which I'm surprised isn't default anyway). I've also seen BBQ grills that require power, and have even experimented with furnaces running on power instead of wood. I have not much experience with this section, but I can help further with your inventory situation.