I found an interesting way to add the extra length to the budget flashlights to make room for an 18650. a 3/4" copper pipe cap presses nicely into the open end of the flashlight.
Behold! The Phlashlite!
I also figured out how to make the clicky switch in the bottom into a momentary pushbutton.
Behold! The Phlashlite!

I also figured out how to make the clicky switch in the bottom into a momentary pushbutton.