Wow, cool. One of the first things I'd add is a flashlight, probably one of the Countycomm $1.00 units that I call the "Countycomm 2" (since it's the second of three lights of this class that they've offered):

http://www.countycomm.com/light10.htm

They're not all that waterproof, but they're reasonably sturdy and the lithium batteries have a very long shelf life, and storing it in a small baggie can keep it dry. I'm surprised one of these wasn't included in the kit. I wrote a detailed review here that covers this model as well as the earlier CC1 and the more familiar Photon II. Everyone should have a few of these lights scattered around their gear.