Just wanted to blow the dust off of this thread, as I found a really cheap vreg'd level shifter recently:
http://www.ebay.com/itm/251384699933?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
And I really appreciate the tips about how to make the project more energy efficient! I have a few Pro-mini based loggers now and have been thinking of swapping out the Voltage regulator there for something with a lower quiescent current.
Although I have to admit I am no where near your ability levels, I have completed a power burn down test of my own, and thought I would post it hear just for giggles. Keep in mind that I had very little electronics experience before this project. Also I am saving all the data to an SD card, which is a huge power burden for the logger, but more practical if I want people to build their own units later.