I would look at the Ravemen CR1000. Beam is actually designed for bar use but it's still a decent thrower, under your weight requirements, and while it won't quite give you 2hr of high mode runtime the med. mode is still around 700 lumens for close to 3hrs. Can't think of anything else that meets all your requirements. $70 retail in the US and of course with "Black-Friday" coming up there may be better sale prices.My current setup is a Bontrager Ion RT 1300 Lumnen on the bar and an Ion 450RT on my helmet.
The 450 is due for a replacement and I would like to replace it with a light that have a tad more lumens.
Since I really like the convenience of the Bontrager mounting system on my Bonty helmet, I looked at the Ion Comp RT which for 120$CAD output 700lumens and only 35g heavier than the 450RT at 135g.
What would be the light worth considering? around 700 lumens and lighter than 150g? My rides usually last less than 2h at temperatures sometimes below -15 celcius.