A 2AA side by side easily fits in a trouser pocket without being thicker than a 1AA light. Most budget 3AA or 4AA light have the need for flimsy plastic battery carriers which are prone to break.
Assuming the same guys would manufacture it who brought us the awesome CQG S1 and S2 ... it is save to assume they know their way around stainless steel with very thin walls.
The S2 has measurements of 89mmx15.5mm, so in the best scenario we get a 85x30x15.5 mm (slightly shorter due to 2 TIR) light which runs of 2AA and has 2x3 brightness levels... if that would not be cool... I don't know what is. If a different driver could be found ... cough (probably slightly too large, as the walls would be thinner than this driver ;-) ).... it could be run of 2 AA /2 14500/ and even (1 AA and 1 14500). Just fuse 2 S2 together at the main tube and keep both circuits completely independent... read 2 switches. The Saik SA305 has a thickness of 53mm the UF MCU-88 a thickness of 48 which is slightly thicker than 15.5mm. ;-) Oh and keep the neutral /no-strobe option. That is all....
If you do a 2AA in a round barrel format, it might as well be 3AA, the diameter of the tube is not much more. Otherwise 2AA might as well be rectangular in shape for the body. 3AA or 6AA would be my preference.
I was only going with 2 x AA because I thought there was potential to operate on 2 x 14500 as well, but it sounds like the voltage range is not feasible. Now I'm all for 3 or 4 x AA. How about a AA fatty? For me it's not just about compact size, but also convenience. The AA battery is just soooo convenient. I'm trying to think like the average joe flashlight user. I don't need, nor do I want, all my flashlights to be the flashaholic, lithium-ion type.
You see, these kind of threads are great for hashing out real world flashlight concepts. Instead of just tossing around ideas here and there, we're focusing them under a topic that is designed to encourage manufacturers/vendors to make them a reality.
From my POV (and I know people here disagree), the photos show something that's still way too wide for EDC. Yes it may fit in a pocket but not really much better then a 2xAA lengthwise (although both are a bit too large if I plan to do it regularly) and I'm not sure the form factor is more comfortable in the hand either. Frankly I see even less need if it's parallel or independent circuits. It needs to be brighter then 1xAA otherwise it's pointless, just have 2 flashlights or 1 flashlight and a spare battery, that way you don't get a needlessly wide flashlight and with the 2 flashlight scenario you get significantly more versatility in usage (plus increased redundancy).
I agree more multiple AA lights is good either way. It does seem to be an area poorly served by budget manufacturers yet would seem to be of interest to many non flashaholics as you say. Even 2xAA lengthwise isn't that well served although you can often use any AA & li-ion compatible 1xAA with an extension tube and some of the name brands are getting close to budget. 2xAA side by side lacks anything budgetwise and is obviously of interest to some and I don't want to discourage them. It's just not really that interesting to me, and 3 or more AA is more interesting but it also seems to be an area without anything good budget wise particularly after the death of C88 which stock wasn't great anyway. Very well made perhaps, but by 2011 the LED was too crap to do it service.
Not molded .... machined... unless you know a cheap way to mold aluminium or stainless steel in small quantities. It has to be brighter than a SC51... otherwise there would be no point in making such a light... how would you cool a 200 Lumen light without the use of metals?