Well I finally have the bike how I want it....I ended up with a 2 wheel trailer to carry 2 battery boxes containing 12 7.5 Ah SLAs, with switches to allow separation of the 2 battery banks, or running them in parallel.
Although now I am riding in between thunderstorms, I have about 100 miles on the bike already, counting my first successful ride to work and back yesterday. My LEDs still indicated full battery after the 11 mile trip to work, and I was able to charge there during the day. Same charge left when I got home, but I did get soaked by a thunderstorm.
My trailer is fabricated from an old jogging stroller, with nice little 12 inch wheels, which I bought Airless tires for, so I won't have to worry about flats. I haven't weighed it officially, but I estimate the weight of the batteries and the trailer at 60 to 70 pounds. Good to have that weight on it's own wheels.
I help a little on the hills, but I still seem to be getting good speed. I definitely have enough battery for some decent range, and I can fashion a small single pack to mount on the rack and leave the trailer at home for rides around the neighborhood. The ride is fun even with the trailer, so I will take off for a few miles whenever, just for the fun of riding.
If anyone wonders why I am using so many batteries, it is because I have a bunch of them....a supply that will last me for at least a couple years if I take care of them, and I may have access to more in the future. In many applications, these get changed at regular intervals just to insure battery back for some critical equipment, and they still have some good life in them. The price is right also. I will always have the option of going to hitech batteries, but for now, this will do.