Keyport Slide revolutionizes keychains
The Keyport Slide is a universal key fob that stores your keys in a tiny rectangular case. Sliding modules push the keys out, and there's even an integrated RFID to allow for remote keyless entry. It's not out yet, but damn if it isn't a good idea. Although I doubt it'd fit all 4,000 of my keys. Right now I just keep them all taped to my jacket. It takes me three hours to get inside my house.