The OP has the diameter already spec'd at 120mm. Does that mean that a specific reflector has already been chosen? Sure would like to hear about it as it will about the biggest differentiater from other thrower lights.
There is not a particular reflector chosen, and that may become an issue. I gues that we hope that a manufacturer manages to source one in China, or has them specially made…
IMHO, a 120mm reflector will look too big for the plunger style! For a plunger, I’d want no bigger than 80mm. In fact, the plastic Rayovac/Energizer/etc. box style lights that are sold in every store have no larger than 3” (~76mm) reflector! If a 120mm reflector is to be used, the plunger light would look absolutely ridiculous! The only way to make the battery tube even remotely proportional looking would be to have all 8 cells side-by-side, and a separate handle. Or, make it with the dual tube design I suggested several posts back. Actually, I just thought of something else that would work. Make it to take 8x 26650 cells! 
Reflector diameter and head diameter are two different things. There are already 100 mm head diameter lights - Shocker, TN42, TN40, etc. I guess you could argue they look ridiculous, but I don't think so. I agree the EagleTac M25C2 Turbo looks ridiculous at 92mm head diameter but that's because of the single width 18650 battery tube.
A 4 18650 width tube and a nicely designed head with finning at 120mm would be interesting to see - I don't think it would be so bad.
Im interested of course .
Of course you have your opinion, and I have mine. I’m just imagining the actual size of this thing. The tube won’t be 4 cells wide. If it’s a 4-cell tube, it will be a little wider than two cells. The head size to contain a 120mm reflector would be at least 2.5 times the width of the tube. Overall, the light will look “oversized”. To visualize this: Think of a Courui D01 with double the tube length and added 50% to the head width. It’s just too big - unless you’re over 7 feet tall.
I agree with Tom. The TN42 has a 100mm head and it looks great. Adding another 25% wouldn’t make it look terrible either. The courui only has a 3-cell tube. 4-cells helps the proportions.
I don’t mind the look of the box style, but normally with a thrower holding it at eye level is the most natural. That’s impossible at worst and uncomfortable at best with a big box.
But do remind that a box makes it more compact, if the TN42 was rebuild in box-format, it could be this size:
(perhaps a separate build for a box-shape lightweight 2x18650 parallel 120mm reflector XP-L HI thrower should be considered at some point, but I can not do that on my own. I’m tempted to make that one recoil even)
Compact, sure. but then you have to hold it like this: 
LMAO…boombox or not to have boom box…that is the question. Both are valid points OP above djozz and PD68.
Why do you hold a flashlight at eye level? I’ve never seen anyone do that. But, you’re going to hold this monster light at eye level? And the difference between a 3-cell tube and a 4-cell tube can literally be less than 5mm of added diameter.
If I am trying to see out past 1000meters, anywhere I can think of in my area will have trees, high grass, corn, small hills, etc in front of me. I will either hold it at my shoulder/eye level, or sometimes raise it high above my head. That’s how I use my Courui when I need it. If I am just going for a stroll, I probably won’t be using this light anyways, but I would have it at my waist.
I am in. 
Depending on price
Why not! Put me down for one please.
I haven’t seen any talk of rough price or rough throw but why not!
Would be awesome to aim for something that can hit 2km
Definitely interested
How about slapping a big head on Q8? Everything about that light is already well thought out, we have a relationship with manufacturer and $40 price tag could be kept.
If TN42 had 25% bigger head it would look even better. The Courui has the perfect proportions for a light, and this BLF MT will have very similar proportions to that! Design wise if it is close to Courui in design, or eve a box design it will be great. Those plungers with narrow handles look horrid. Everything else should be fine.
I’m interested.
Count me in for one unit please.
Agreed, if only my courui was properly modded - sad really, my favourite looking flashlight, and yet since I got my sniper I never use it…………….it’s just so under powered.
I know the project has started with a roughly 120mm reflector - but could you clever guys not just mod a ‘host’ courui and make it actually work like it deserves to?
Seems to me it pretty well ticks most boxes already, it’s just the terrible performance that needs sorting. I know there was an issue with some peoples reflectors, but of course there is no guarantee that ‘any’ bulk bought reflectors will all be good.
Anyway, just an idea
David we understand this is will not have the same appeal as the Q8
For lights with a reflector you say there is ample choice.
This is going to be an extreme flooder surpassing the TN42 at a lower price.
I really hope you will still engage as you did with the Q8 even though you are not liking what it could be looking like
I fear the reflector, driver and LED alone will costs manufacturer more then $40 and we need a lot more material for the housing.
When form factor and LED are choosen we will do a rough calculation to see what this one would cost (as was done with the Q8 bit that was much easier to guess 
)