Tom, that is a most impressive tank. That tank and how you've utilized it is simply awesome.
I am a fan of relatively self sustaining tanks - I don't use CO2 or regularly fert. I just want a seeing-hole into a fish's natural environment (or as close as I can get it to be).
I could see my 20g reaching that level of hands-off if my GF didn't insist on having so many fish. Although the plants will do fine, I can't sustain a predation cycle with the amount of fish I have. Feedings are absolutely necessary.
Clearly, your plant-to-fauna mass ratio is highly in favor of the flora.
Very inspiring, thanks for sharing!
I am highly inclined to try something like this with my next tank.