Excellent update on your fine article, thanks Eric!
Have to disagree regarding your points on NiMH batteries, though.
I've now flown now for over 2 years with them (including a dedicated
transponder battery) and I love them. Weight is about 60% of sealed
lead-acid, same for volume. The big advantage I see is in being able
to quick-charge them with 2A in a couple of hours very safely with
cheap automatic chargers available for example from all-battery.com or
ebay. I fly with 2 batteries for instrumentation/radio, each 5AH and
one for the transponder that has 10AH. One of the smaller batteries
is in the tail. Having much less mass in the area behind the
headrest is another plus. Shop around and find that the prices are
affordable and pre-wired 12V packs are offered.
I have not found the higher discharge rate in storage to be a factor.

Herb, J7