1. Chip the items of importance to you with an RFID tag.
2. Add a solar-powered RFID reader to the lining of the bag, with external indicator lights.
3. After filling the bag with your stuff, press a button to tell the bag "This is all the stuff that should be in the bag". The bag then reads all the chips in the bag, and stores them in memory.
4. Later, you can tell if you've put everything back in the bag by looking at the indicator lights. If the light is green, everything you initially packed is in the bag. If the light is red, you're still missing something.
Anyone know if this exists?