I EDC a very small Eze-Lap keychain diamond sharpener (with key chain removed), that I tuck into a small slot on my mini-kit pouch.

Be careful with this small sharpener, it is very easy to cut your support hand when using it (learned the hard way).

This sharpener can be seen here http://www.pacwestoutdoors.com/eze-lap-key-chain-sharpener-75.html

Mike