I measured mine again and I dont know what I did last time but my own numbers were completely incorrect.
My duracell battery measures 33,1 without the nub and 34,2 with it
My grey (not blue as I said earlier) trustfire is in fact tilted to one side and measures 35 mm with the nub and between 34.1 and 34.6 without the nub, depending on the side I measure it.
I think it's safe to say that the grey trustfires are bad quality, but they were also very cheap so I get what I paid for I guess.
Anyway, the Bestionone and AW look interesting, are these the AW you have:
I just bought the AWs to compare to the bestinones. I certainly would not buy any more at that price. I wouldn't even buy them if they were the same price never mind 5 times as much.
Why not consider LiFePO4? In my E15 EDC I use Tenergy LiFePO4 and it works great. The tested capacity of the cells is pretty good, kicking in on average 595mAH @ 0.5A across 6 batts I have.
In the category of protected 3.7 V Li-Ion rechargeables, both the AW ICR 123 Rechargeable and the Solarforce 16340P (black lettering) are 34.6 MM in length, including the positive nub. They are the smallest ones that I've found in this category, although as others here have pointed out, there are some other options in the 3.7 V IMR and 3.0 V LiFePO4 chemistry types. A little side note - the newer Solarforce RCR123's (blue lettering) are much larger and (diameter and length) more expensive but have actual capacities that are much closer to those stated on the label. Unfortunately, I have found that they don't fit many of my CR123-size lights. Although I don't own a Fenix E15, both the AW ICR 123 Rechargeable and the Solarforce 16340P (black lettering) fit all of my CR123 size lights that can run on 3.7 V rechargeables including my 2 smallest battery tube applications, a 4Sevens Q-mini 123 and an AmiLite Cuty 123.