Sorry Mitko - don't mean to sound upset at all. I know you're bizy and probably doin all this on a cell phone. But I'm very interested in get'n/finding some W2's. Whatever info you can provide, appreciate it!! Thanx!! 
Interested in building these for anyone?
Phew…
I dremeled, drilled, lathe-ed (without a lathe…), sanded and filed the hell out of the pill, DTP board, battery tube, switch spacer and retaining rings and i think it’s ready for assembly now.
I’ll share some pics tomorrow.
Please don't tell me it's
No, it’s not a carrot on a string. (?) 
Change carrot to flashlight. ;)
Don’t forget to share numbers also… This is a lot of job and I really don’t see how it could be simpler than just ordering 26mm mcpcb with a lot of clearance for reflector and adding a copper chunk beneath it on that nasty aluminum pill but I am very interesting to see what you did.
I’m not sure if this was more work, but at least i didn’t have to wait another month for parts and it only cost me a DTP board, although i also replaced the switch with a smaller footprint one to make a spring bypass.
I’ll get my camera and post pics later.
Okay, here’s some pics then:
The butchered DTP board.
The butchered board, pill and driver retaining ring.
So the leads go trough the outside of the pill and bent back to go on the DTP board
I’m still considering some screws to fix the board to the pill though.
Driver retaining ring opened up for Nanjg 105, with the 7135s near the edge.
Under side of the board and pill.
Looks a bit messy, but it’ll do just fine.
Didn’t want to touch the reflector, but decided to file the edges down a bit to gain some more room for the solder joints on the DTP board.
So there it is, there’s a decent gap for a soldered wire. 
Here the reflector rests on top of the DTP board
In all there is some room for a thin spacer too, if that’s necessary for the best focus.
No picture of the battery tube, but i took off around 1.7 mm of the front end.
It can now be screwed tight in to the head, everything fits now.
Hi jerommel, I have my flashlight on the way, wanted to put driverNanjg 105, you have to modify it to place it? Or fits well? , This, regards!
Retainer ring is always difficult with 105 driver:
There is not much of it left…
Nice mods guys. Love them. That retaining ring is hanging in there by its teeth. 
Wow, the butcher job is actually not bad at all! Like it!
Just drilled some more holes in the pill and DTP board…
Board is now fixed with tiny screws. (flush / counter sunk)
I’m making a habit of doing that since i shorted my MT-G2 C8 because the PCB cut the wires when i screwed the pill tight to the reflector…
In this light the same could happen.
Jerommel,
You know when you said that you’ll not buy 5$ 26mm mcpcb? Well it seems like you spend more than 5$ of electricity for that mod
But very interesting indeed but it will not be better than simple 26mm mcpcb mod(better heat transfer, larger copper board).
But yes same ugly aluminum pill like mine… Donat hole in the critical place for heat transfer(below emitter where the greatest heat happens).
For proper and successful modding, and because of mentioned bad pill at least one minute of stable output test on lux meter is must. Mine as I said has 260 kcd for first 5 seconds than it starts dropping fast to 150kcd after 30 or so seconds. That of course will change instantly when fat 26mm mc arrive.
I tweaked some things , it’s now making 210kcd with the stock emitter . Of course it could do better , but it is clearly a super cheap flashlight for what it offers . Heatsinking is pretty good , i don’t see any drop caused by the temp of the emitter .
U4 emitter and AR coated lens would help , and even as Mitko mentioned a xp-l dedomed would throw even better.
With 26mm mcpcb?
Yes . It requires quite some time to sand the pill and make a nice flat surface for the mcpcb , but it pays off in the end
The one that will modd with 16 or 20mm pcb should really pay attention on heat transfer. Donat hole in the middle is simply terrible.
Hardly wait for my 4 x 26mm ones + additional 3 x Mitko super throwers.
Also in meantime our member Driver have sent me original good old XP-G2 S4 2B emitters. So I hope that I will touch or surpass 300 kcd mark with them.
The bottle neck of the heat transfer is the LED itself, not the transition from the DTP board to the pill.
The surface area of the DTP board and the pill shelf is many times larger than the surface area of the LED thermal slug.
Sure, the pill shelf surface is not perfectly flat and has a little dent in the middle, but when you make sure the DTP board is fixed tightly to the pill (i use screws) and with a little thermal grease, it will be fine.
I do wish i had a good old XP-G2 S4 2B though…