You are correct, this couldn't initially. What the platform I outlined has is flexibility and cost. But mostly flexibility. Probably the high end of port density would be ~40 (using dual port nics) and this would be for 2u. But you could start to run stuff on the switch that his historically run with ha proxy, varnish, nginx, etc. If there are sata ports, one could code themselves a backblaze pod that doesn't suck and include grep directly on the stata port.
Arista came out last year with something vaguely(although lacking the modularity of cards)similar to what you've got in mind. I think it was originally targeted for high-frequency trading apps where proximity of the colocation such as 350 Cermak in Chicago makes a huge difference in latency. I never heard much more about it though.
