Emulator

Is it possible add a note if a save state is occupied or not when you pick a slot?

This should be implemented for the on-screen display messages that appear in the emulator (if you have it enabled) and it should implemented in the "Emulator --> Load State/Save State" menu.

Personally I use multiple save slots for varied things, but I have to constantly keep picking a slot and loading it first to see if it's occupied to avoid overwriting a used slot.