Why limit yourselves to just off the shelf Pila or SF LA's? There are other bulbs you could use (I might have a few that I will be testing from Carley over the next week for the update to the 8AA-2D WH/SL regulated adapter review thread /ubbthreads/images/graemlins/wink.gif ). Other 3.5, 3.6, or 3.7v bulbs might be used in a hack. I was looking at the Brinkman Maxfire I bought (lousy eyesight, I can't see worth a darn in the weak lighting of retail stores) and I have to say the lamp module looks like it could be easily (well not too difficult for hackers) taken apart to install another bulb. Sheesh, you ought to see how badly centered the T1.5 bulbs are in the module in my Maxfire...leaning tower of Pisa!, same with the PR base mounted bulbs that come with the 8AA-2D adapter. Only difference is that with the standard M*g reflector, all the flaws of misalignment, filament uglies, and such; are painfully evident.
It would seem possible to use Pila??? if they can fit snugly (diameter maybe too large, even if you peel off the 2nd outer plastic layer), but if you went to rechargeable 123's you could potentially mount some seriously high lumen lamps in the lowly Maxfire. Only problem would be, for how many minutes would it take, for the plastic parts of the module to start to melt /ubbthreads/images/graemlins/frown.gif ? BTW, I measure an inside diameter of approximately 18.5mm for the Maxfire body tube, so Pila's or most 18650 Li-Ion cells should fit!
Let's see, a bare/unprotected rechargeable LG Li-Ion 2400ma 18650 cell could easily drive the Carley 1122, T1.5 size, 3.5v/2.3a, 8w bulb for just under an hour at around 140+lumens. 8w is almost as much heat as generated by the stock bulb in the M*gChr, which has a large metal reflector to insulate the plastic parts from searing heat of the bulb. I'm afraid the lens and plastic parts of the Maxfire could not handle extended runtime for such a setup, but who wants to try and melt one for cheap thrills /ubbthreads/images/graemlins/evilgrin07.gif
Time to start a new thread, Maxfire $16 mod to $20 light ($10 Li-Ion cell and $6 Carley bulb); spanks SF E2e, in throw & output /ubbthreads/images/graemlins/grin.gif? Yet another 'Mini-me' version of the M*gChr that fits into your pocket, cause it's so small, hehe?