Update and answers
After a few days of pocket use the size and weight do not seem to be an issue – but I would still prefer smaller and lighter version for a keyring style light. On the negative side, I have had one inadvertent turn on so far. I was putting wood in the wood stove and when I crouched down I noticed the light was shining through the material of my pocket. I have no idea if the crouch caused it or if it had been on for a while. I also don't remember the last use to know how far past off it was left – but quite honestly don't think anyone should have to think about those things. I'm sure that someone can engineer a twisty with a tactile and stable off position that would not detract from the simplicity and reliability of that type of switch. As far as the test unit, it does appear that the o-ring does not provide enough resistance to keep the head from turning when carried in a pocket.
No CR2 yet – man those puppies are expensive! Maybe I'll break down and order a few of the more reasonably ones from Amondotech – or maybe a couple rechargeables from AW. Speaking of Li-ion rechargables, one of the AAAs might be pretty nice in this light since it should handle the voltage. (MJ is 3.7V OK for this light?)
Offroadcmpr – not sure which bin my TLE-5 is. It's the side emitter version and was purchased from LED-Replacement last summer if that helps.
Pokkuhlag – I think the photo may be misleading because of the sharp difference in color. There is very little difference in the diameter in the 2aaa pacific tube and the 2aaa mini-mag. I couldn't find my calipers quickly but for some rough ruler type measurement, for the open end of the tubes I got a .5 in for the mag and just a hair more for the Pacific. The knurling is more pronounced and raised on the Pacific so at the widest point it may be about a 1/32 wider than the mini-mag.
Tungsten – good catch on the "H" imprint on the positive contact of the head. There was a letter included with the test lights that indicated there would be three power level versions of the Pacific and the one sent was the "High Power" version which was the middle of the three. I assume there may be something in the works for the brightness junkies – but you'd have to verify this with MJ. I think the current brightness of this light is very good for a "walking at night" type level – bright enough to see without killing the night vision. Personally I wouldn't want anything much brighter without a two stage option – hint hint - again.
If I missed anyone's questions please ask again.
All for now, hopefully I can start some runtime testing with pics tomorrow or over the weekend.