excellent review. i really enjoy reading a Pro's review of headlamps.
i agree that the e+LITE will never replace my '06 ZipkaPlus as my always_carried_in_my_pocket lighting device, particularly for the reasons you mentioned regarding battery life of the Li coin cells.
1) have you come across a Petzl stated or empircally determined length of "burn" time for the single RED LED? If not, any guesses?
2) can you please share your source for thirty cent CR2032 batts? i can find them in any Qty, even just one, for ~$0.90 each (BrightGuy.com), $0.69 each for 10-90 qty, and in >100 qty for $0.49 each - both larger Qty prices from InfiniteLights.com
3) does it really take hours and not just 10-20 minutes (or even less) for the batteries to cool enough so that aspect of any battery's internal resistance is reduced, thereby allowing brighter light output once again? i've never tried this with a Li coin cell light, but have tried it AA alkaline batts and it's usually just a few minutes (10-20 min yielding much better results than 2-3 min, IME). Of course, the shorter the cool-down time allowed, the shorter time the brighter light is output (subject to inherent upper limits of time, depending upon how long it takes to cool and how much stored energy is left in the battery).
i would have thought that given Li batts low thermal mass coupled with the higher surface area to volume ratio of a tiny Li coin cell, which affects heat transfer, that it might have been faster to recover. i understand that other factors, such as packaging and air volume/flow near the batts come into play also. i've never tried, so i'm probably mistaken for some reason i haven't yet reasoned out.
again, many thanks for such a fine, professionally performed and well written Review.