I would create a reduced size drop-in module, similar to a P60, but scaled down. This way you could customize the light to whatever your needs were. I'd fit it to a AA/123 combo body. Then I would design a custom resistor piece that screwed on in-between the head and body that could be user customized with replaceable resistor boards. Tail clicky. 2 mode.
So, a AA/123 light that could take drop-ins. User selectable resistor modes. About the same size as an L1. Completely upgradeable, customizable to new technology.
So, a AA/123 light that could take drop-ins. User selectable resistor modes. About the same size as an L1. Completely upgradeable, customizable to new technology.