I'd say use an Arc AAA or Peak Matterhorn if you want a 1AAA light for easy battery swaps, an L1p if you want something powerful, otherwise a Photon II or clone. I'd skip the L0p and the Freedom.
I've got a Photon Freedom on my keyring and a Peak Matterhorn in my
Mission Wallet along with a Leatherman P4. The Arc and
Peak Matterhorn single AAA lights are very well built and are easily carried.