[The Nitecore P36 and the Fenix TK35ue both] run over an hour putting out over 1000 lumens. That's one of the best things with higher powered lights. You don't require turbo to put out a lot of light.
Almost all of the 1000-lumen, 1x 18650 flashlights that are designed to have a good mix of flood and throw will have some sort of step-down. Some use a timed step-down. Better models use a thermal sensor, stepping down (and back up) as the temperature requires (or allows). Most of these lights cannot give a full hour of runtime at 1000 lumens. They just don't have enough heat-sinking to dissipate all the heat their turbo modes generate. Flashlights designed primarily as throwers do better. Those lights house a deep reflector in a large head, so there is more room for large heat sinks.
I went shopping last month with the intention of buying a Zebralight. When I found that the neutral-white 18650 model I wanted was not in inventory, I purchased my second choice, the Nitecore P36. It's a nice 2x 18650 light that runs the neutral-white MT-G2 LED. It claims a 2000-lumen max output, but the reviewer
selfbuilt tested it at 1850 lm. His test also showed it dropping into a gently declining direct-drive output mode relatively quickly in its highest modes.
The P36 has 10 different output levels, nominally ranging between 20 and 2000 lumens. The brightest mode, level 10, slipped into direct drive almost immediately after power up in selfbuilt's test. Level 9, the next brightest level, tested at 1600 lumens, and stayed flat for about 20-25 minutes. Level 8 tested at 1300 lumens, and produced that output continuously for an hour. From there, it entered a direct-drive decline, reaching 50% an hour later.
Level 7 may be the level you want. It produced a well-regulated 950 lumens for a solid two hours. After that, it began falling, reaching a very useable 50% output 45 minutes later.
Note that selfbuilt measured runtimes using a pair of 3100mAh batteries. Switching to 3400mAh batteries should extend his runtimes by almost 10%.
Nitecore recently released a new light, the
EC4, running a cool white XM-L2 LED. It uses 2x 18650 batteries, and weighs about 2/3 as much as the P36. The smaller size and weight may bring it into range for you. The smaller weight, however, may also mean that it cannot maintain it's maximum 1000-lumen output without stepping down. I have yet to see any data on its runtimes.
Nitecore also announced—but is not yet shipping—the
EC4S. It will use the neutral white MT-G2 LED in the same body as the EC4. I will likely buy that one.
I hope this info helps. If you can get by with the step-downs, Zebralight may be a good choice for you. But if you must have a continuous 1000 lumens, you may be drawn to one of the 2x 18650 formats.
Good luck!