Nice work, Pieter. You're right that my simulation assumed bandwidth for 'block' messages isn't the bottleneck.
But doesn't Matt's fast relay network (and the work I believe we're both planning on doing in the near future to further optimize block propagation) make both of our simulations irrelevant in the long-run?
Or, even simpler, why couldn't the little miners just run their block-assembling-and-announcing code on the other high-bandwidth-side of the bandwidth bottleneck?