I'd suggest building a 2C Maglite ROP Incan. This will give more throw than any LED on the market (except exotic aspherics that aren't very practical) and a repectable 40 minutes runtime in a surprisingly small package. For investigating tree lines, the warmer color temp and broader spectrum of an incan still provides vastly better contrast compared to LEDs, at least for the next few years
I'll cut and paste in a "recipe" for how to make one:
From lighthound.com:
* 2x
AW LiIon C Cells $48
*
2x Pelican Hi/Lo lamp kits $18
*
Anti-Reflective Coated Glass $7
From Kaidomain.com:
*
MOP textured reflector with 8.4 mm opening $15
OR you can get the original MOP reflector from Fivemega on these forums. Better beam quality, and faster shipping, but more expensive ($30 shipped)
Charger Options from Kaidomain:
Single C/D LiIon Charger - $15
2Bay LiIon Charger - $9. You can charge in one bay only using magnets, or both using external leads, but it's slow as it's meant for smaller cells
2 Cell LiIon Charger - $10. Only recommended if you already another charger, even a slow one, in case they get out of balance.
How to make extra room for the cells:
1) Cut down and/or compress the tailcap spring
2) Remove switch, remove retainer ring, reinstall higher up/closer to bezel
3) Use dremel tool to remove as much excess material from the base of the switch as possible
OR
Buy this extender for $13
How to make cam focusability more useful:
Grind down the cam on the reflector you buy so that the slope is about half as steep. This will limit how far the bulb can defocus so you never see any nasty "donut holes".
Total cost is between $90 - $160, depending on your reflector choice, and whether you still need to buy a Mag 2C host and charger.