I buit one of these using a maglite solitaire. It was powered by a 12v "N" cell and had just enough room left over for a simple driver.
Look at the parts in the picture.
#9 is the mini bulb and it's leads just push into part #8, which is the on switch.
The way it works, is the head is rotated to focus the light beam and if you turn it all the way clockwise, it screws down on the reflector, part #6, which presses down on the lamp holder, part #8, which has a side spring that breaks contact with the aluminum body, if pressure is applied to it; breaking the circuit.
What I did, was remove the light bulb and push the bluray diode's leads into the same socket holes. I made the LM317 driver circuit small enough to fit into the battery tube. The driver went in first, followed by the 12v N battery. -This is sorta like the Kipkay flashlight hack, but with a driver and in a Solitaire, instead of a mini.
Now, the focusing part...
I took the lens out of an Axiz module and pressure fitted it into a 1/4 inch rubber grommet, the kind with a channel cut in the center on around the outside. This channel is important, because it grips the edges of the Axiz lens and holds it tightly in place.
Now with the laser lens in the center of the grommet, remove the lenses in the Solitaire's head and, taking a tripple "A" battery, push the grommet/lens combo into the bottom part of the flashlights head. When you're done, the laser lens/grommet will be pressure fitted into the front part of the flashlight head.
Now you can focus your mini laser by turning the flashlights head, just like when it was a normal flashlight and you can turn the laser off the same way. This laser had a lot of limitations because of the lack of any heatsinking, but it worked well for short periods.
I wish I had taken pictures of it before I cannabilized the laser for another project, but I would be happy to explain the build in more detail if needed.