The U4 in an hd2010 sounds awesome, and I’m looking forward too the Mtg2. Today is the first I’ve heard of it. What are the dimensions?
Any dimensions? 
Talks about the MTG2 as well
The U4 at Cutter seems to be something completely different, not intended for flashlights, requiring a higher voltage. Ooops, didn't pick up on the details. From the other thread, the MT-G2 also seems to have the same problem...
I found this: Using CREE XM-L U3 LED
http://www.sunwayman.com/html/products/201211/99.html
also these:
http://www.crelant.com/a/English/Product_series/7G%20Series/2012/1102/34.html
And XinTD C8 with U3
http://www.intl-outdoor.com/xintd-c8-xml-u2-910lumens-multi-modes-flashlight-p-308.html
At least 2 more Crelant U3 models are available at I-O here: 7G3CS and here: 7G6CS. Also new thread here: https://budgetlightforum.com/t/-/13204
This explains all the price drops in recent weeks to flush inventory.
so is this just the beginning of a flood of lights? that XinTD C8 looks very tempting but if there are going to be more soon…….
ken
The XinTD C8 has gotten great reviews/recommendations here. Not sure of that 1000 lumens rating is real OTF for the U3 1C - that seems like a strech over the 910 rated U2 1A. But that brass pill looks incredible, and with a standard Nanjg driver and high qual host and reflector, it's a great deal.
If those lumen #'s are real with a stock 2.8A driver, it can do a lot more. I've gotten really good at piggy-backing 7135's lately, so this light is a prime candidate for adding a few - I would add 3 350 mAh's to get it up to 3.85A or 2-3 380 mAh's for 3.56A/3.94A - this light should be able to take it. I'm running 10*7135 380's for 3.8A now in 2 C8 lights w/smaller cheap alum pills and they can run comfortably with a 6 minute test, gets hot but not too crazy. My C8's measure 3.72A at the tailcap w/fully charged unprot. Panasonics - not much drop. Probably lose more amperage over the tailcap though, so I suspect less amperage is actually getting to the LED.