Fasttech offer a lot of option but not XM-L2.
Get the Convoy C8 at Banggood
There is even a thread here talking about that.
Go with any Convoy that you like, I’d rather get a Convoy S2 or S6, at banggood again they have the 2 group driver (and firmware can be flashed but it’s another story), XM-L2 T6-4C (great tint). They’re still too big to be carried in a pocket (get the Tank007 E09 for that) but it’s great in a coat pocket. And the form factor is closer than your ultrafire that you wanted first.
Getting for a 8*7135 driver will be bright on high but it will get hot too, runtime on high is not an issue as it will be hot before you get low voltage warning.
But medium at 33 or 40% will be bright enough.