Has anyone tried this driver from Lightake.com? It's good for up to 8.4V but it doesn't say what the output is.
It's sku 29490
I don't think it could really handle 8.4V, I think it's a mistake.
It looks like a simple pwm dimming driver.
Good point. Now that you mention it I didn't see a buck on it to bleed off excess voltage. Why is a multimode 8.4V driver in 17mm so damned hard to find? Single mode are easy to get. 
How 'bout this one?
The LT driver looks a lot like the one in the TR801... which I ordered a while back.... good driver for 1x18650 and XR-Es.... don't know if anyone tried 2x16340 in their 801...
Almost but that’s 20mm on the base PCB and 17mm on the top PCB. Plus it’s only 1A. I have some on the way from DX that are true 17mm and good for 1.2A. We need good XM-L multi-mode for 8.4V in 17mm.
Amen to that. And please please let it be Atmel controlled too 