Could go in to Tips and Tricks or into Lighting. We'll see what the mods do.
Button batteries? I would think that AAAs would cause the balance to be off. I think that most (all) batteries have the same volts (or is it watts?) and vary in how long they can be used before draining. So the limiting factor might be size, what ever it is you want, and you'd put in the correct battery case/connection to the leds, and if you go for larger, change it less often, smaller change it more. Although LEDs are pretty eficient, so maybe you'd not have to change very often in any case.
The Lady with a Lamprey
"The powerful are exploiting people, art and ideas, and this leads to us plebes debating how to best ration ice.
Man, no wonder they always win....." Lonesomebri