It would probably be quite a bit less impressive than the G2. 15 or maybe 20 lumens for an hour or something like that.
Of course, you could use the Bug Out Gear Lux III module in it for good brightness and limited runtime but I think a lot of folks looking for a light like that would rather pay a bit more for a host such as the E1E with the KL1 head or something 'nice' like that.
While the G2 is impressive for the price, it is kinda bulky and if I'm gonna have bulk, I'd rather have some decent runtime and output.