Look at Laughing Rabbit Inc.
http://www.laughingrabbitinc.com/company.htm
Check out the Photon Mico-light, I think that will be what you need and if not, take a look around the site, I think you will be impressed.
I have used the Photon II and Photon Freedom for over 3 years now without any problems. I even hung up a Photon II on a ceiling fan during a black out because of a tornado and it burned all night without a problem or a battery change.
I have also used the Photon I and their newest X-light Micro, it is ALL good.
The keychain light I have not used, but if it runs like the other products they sell, you should have NO problem.
Right now most of the micro-lights are 100% brighter than the ones they sold last year.
I have some of the new ones and it does make a big difference.
What is also neat is the signaling mode and different beam brightness, controlled just by squeeze. Neat stuff and VERY dependable.
If you are buying a few, please e-mail Amber:
amber@laughingrabbitinc.com and tell her Pastor Marko from the IntoTheWoods Book Project sent you. They LRI is a book sponsor for our project.
I hope you find what you are looking for Agent Iron.