Mission Bicycle Company carries this U-Lock Wrench which fits onto the end of Kryptonite Evolution and Series 2 U-Locks. While I love having tools at my disposal, can't say that I'm always psyched to carry them around. Pretty nice that this add-on wrench component becomes one with your U-lock and weighs in at only 5 oz.
With the leverage of the "U" removing a wheel has just become impossibly easy. No extra tools needed to change a flat on the fly.Smart stuff!