What 5mm led lights are easiest to mod?

[paulr]

In terms of swapping the leds, that is. Preferably 1AAA format, rugged and waterproof. Obviously coin cell lights are the easiest, but their drawbacks are well known. I've gotten interested in setting up lights with some unusual led colors.

 

[IsaacHayes]

Dorcy 1AAA old style with reflector. I don't have any experience with the optic model. Probably not very waterproof.