Kind of pricey. How about a couple of Odysseys?

That's like making the first customer pay for the administrative costs of "earning" the STC. If they get 2 or 3 customers pay it, its all gravy from there.

I looked at using two Odysseys battery's in series, but I didn't see much of a weight savings in that configuration.

As far as that STC'ed Li battery (for the A 36) I don't how you can ever justify $6,000.00 plus, for a battery. It's not permanent, you will have to replace it in 5 to 8 years. I have been accused upon occasion (falsely of course), of spending money foolishly by my significant other, on motorcycles, off road cars, and air plane parts, and other "investments", but a 6K battery is just too rich for a consumable.