So it seem like the price difference between building them and buying them is not much different.
The only thing I can think of that is a benefit is you build what you exactly want?
Thoughts? 
So many lights are sold with blink modes in the UI or ugly tint LEDs. Choices are improving In 18650 lights but still limited In AA lights. One of the reasons for group buys is to get lights built with better ui’s in numbers that generate a custom light at a discount price.
Thanks for the info. I don’t know if I’m ready to jump to other types of batteries yet. Right now I don’t see the benefit, that’s why I want to stick with AA or AAA.
Look at the 15mm diameter BLF special driver.
(scroll all the way to the bottom of the page at MtnElectronics for info and links; be patient if you want one, they’re built as time allows and needs must)
That exists because there are several decent hosts for AA emitters — flashlight bodies that are tolerably well made for the ($2 or so) you pay for them.
But they come with “Disco and SO-SO” drivers (strobe and poorly or wrongly made “SOS” modes) that you end up turning on by mistake, or that the light jumps to the next time you turn it on after using it on bright (“next memory mode”), or that you have to go through to get it to turn off. Almost anything you get cheaply made from China these days still has those driver modes.
Put in the 15mm driver created to work well in that size light, put in a good emitter — and you have a decent flashlight.
The benefit. Picture the alkaline display at HD, Lowe’s, Walmart, Costco, grocery store, convenience store, gas station and multiply that by the tens of thousands. Awesome convenience of course. How many places can you think of that recycle them and how often do they just get pitched like a cigarette butt instead, not forgetting the packaging? A rechargeable AA cell(14500) holds less energy than an alkaline but can be recharged hundreds of time before needing replacement. Now picture the pile of a hundred AA alkaline cells you bought instead and the comparative impact on the environment. Picture that pile added to the millions of others generated by like minded people. Chargers can plug into mains, 12V, and USB sockets so no need for the trip to the store. The cells last 10 years, how many times have you seen white crust covering half the cells sitting in the drawer or rotting the inside of a device.
This isn’t a “hate” on alkalines but “I don’t see any reason” should more often be “I’m not looking for any reason”. There are plenty of reasons and good arguments for both.
If you want to stick with AAA and AA size, use NiMH.
That is well put, and in addition to the performance boost 14500 can bring with a FET driver or even a 5 or 6 7135 driver, is the main reason I do not care about AA alkaline for a “must have” in a small light.
Some people worry about the end of society and such for reasons to keep AA, but if that happens we got bigger issues than what kind of light you can get batteries for. Joule thief circuits can be built for general lighting with a big hot nail as a soldering iron and a little light goes a long way in a total darkness situation… So to me that argument is moot.
What gets me is that the power density of 14500 is so much less than 18650’s are. Volume of an 18650 is 16532 cubic mm. The volume of a 14500 is 7693 cubic mm. This is about a 1:2.14 volume ratio. If the LiIon chemistry is the same, then the theoretical 14500 mah should be around 1635 mah for the same chemistry/density, when compared to a 3500 mah 18650. I may be wrong in my calculations as I am not an engineer or anything, but even at a 20% reduction in mah due to scaling issues, there should be 1300 mah 14500’s available. 1300 mah 14500’s would be twice as nice as the current ones… Good luck finding even an actual 900mah 14500 though…