In my experience with an SK68 clone or two their drivers won't fry with li-ion cells. The emitter will, though, because it is held thermally crucified to a thin shelf border in its hollow casket-pill. The drivers also do not feature low voltage warning or cut-off for li-ion so I don't recommend using them in.

I think you may want to ask yourself: What do I really need? What am I up to for?

I gave you a fairly good and inexpensive solution in my first answer here but I see the flashlight bug may have bitten you already. ;-)

Cheers ^:)