Consider the Knog Quokka (an Aussie company. obviously),available in the USA only from REI. Rechargeable without a cord(plugs directly into a USB), light (under 2 oz) and very compact. Can be locked.
Thanks. Rechargeable is generally not a good idea for something you're planning to stick in a kit for years. Plus, with some exceptions, like "dual fuel," then you cannot also include spare batteries. I prefer lights that are going to be stored take lithium primary batteries.
Also, while that's thin,perhaps, it isn't going to pack down compactly I don't think.