I have a SF L2, and I was hoping that someone would make a new head for it that would give it more lumens. How expensive is it to have someone mod one?
A huge +1 for an MC-E in the SF L2, there have been a few demonstrated here and they appear to be excellent. It should get 500+ lumens OTF if driven hard & well-heatsinked. If I was to get my SF L2 modded, it would go to 'Milky' for:
MC-E emitter (I think that the existing reflector is reasonably appropriate for this LED)
bored through to take 2x 17500 LiIon rechargeables (comparable in length to 3x CR123, yes the body should be long enough once the driver is removed from the body)
installing a new 'buck' driver in the head appropriate for ~7.5Vin (The existing driver doesn't run at optimum with a single LiIon rechargeable, and is severely overdriven with two LiIons)
changing the resistor in the tailcap to provide an appropriate low level
After this, the light would perform at optimum with 2x 17500 LiIon rechargeables (~7.4v) and 3x CR123 primaries (~7.5v) for backup.
It would end up being a bit expensive, but would be pretty much a dream light IMO.