Naysen, with that, you've moved me back into the Powdery camp. There are two different Powdery Mildews and the one we're talking doesn't have the fuzzy white growth:
http://ag.arizona.edu/plp/plpext/dis.../tomato/pm.htm
The high humidity inside the plant canopy would be ideal for mildew and the thick growth probably kept your preventative sprays from protecting the leaves.
Any sulfur formulation labeled for tomatoes and powdery mildew should help. I know you are aware of the caveat "do not spray when it's hot (>90F, especially if low humidity) or use sulfur if you have used oil sprays in the last 2 weeks (some say a month)". I sprayed my worst looking row of plants tonight with flowable sulfur. It's amazing how fast that yellow creeps up the plants.
As far as other organic fungicides for mildew, I have had good luck with Neem, but I know that is in your spray arsenal already and not been a great help. I would also like to know of an alternative to sulfur, maybe Paradatz, or others, can suggest an organic cure?
Steve