All LED's are not the same. Newer LED's are much more efficient and give more lumens for less power. A Cree XM-L will easily output over 500 lumens at around 1500mA power input.
Given that your average CR123A has about 1500mAh of power that gives an approximate 1 hour runtime. Of course, intermittent use, heat sinking, ambient temp, and other factors will affect this.
However, for sure it will be longer than the SF old days high power lamps that only ran for 15-20 minutes. If they use any sort of power management they will easily get more runtime at a lower power as the battery drains.
See here for info about output for various LED's.
http://flashlight-wiki.com/Cree#XM-L
A larger bezel for an XM-L makes sense since the XM-L is a bit floody and it would need a bigger bezel to give it some extra throw. Not so good news for all my holsters though!
Oh yeah, before the XM-L one company stuck 3 XP-G LED's inside an X300 to get 1000 lumens for 20 minutes using special IMR rechargeable batteries. Now you could get the same output out of an XM-L or three for less power with a longer runtime.
http://www.oveready.com/custom-flash.../prod_211.html
Dennis.