Modify your keys to fit in a leatherman. This is a real clever way to pack some spare keys around. You can fit up to six keys in one mini multi-tool.
Re-assemble the tool substituting the keys for the tools. Be careful of three things. 1) Be sure you put a washer in between any metal-on-metal contact. 2) Make sure you place the keyring attachment piece somewhere where it will not interfere with a key. 3) Most importantly, remember to leave a gap in the middle of each side for the pliers/cutters to fit into when you collapse the tool. ( I placed two keys all the way to one side, then a bunch of washers and then a key against the other side.
One little tip: If there is a skinny leather punch or mini screw driver piece, you can stick this through the hole when re-assembling the tool to help keep the washers and the pin in place. This also worked well to wiggle around to get everyting to fit together properly.
I was thinking for my next attempt to use a slightly wider, folding style alan wrench set and try to get a bunch on each side.