At OpenSourceDays last weekend here in Copenhagen Jacob Brouer presented his work on
getting 10 Gbit routing going on Linux. His point of departure was a full-duplex 2 port solution.
The result was that routing 40Gbit/s with a packetsize of 1500 is doable. Reducing the average
packet size to the internet average the performance would drop off obviously, but things are
getting quite close.
As far as i understood, his company is looking at this ~6000 dollar setup as a alternative to 60000