Enlighten me... a 1U server can handle nearly 1Gbps of traffic. BGP anycast - a solved problem. How many different locations do you need? For USA - Chicago, NYC, WashDC, Boston, LA, Phoenix, Dallas. In Europe - Amsterdam, Frankfurt, Berlin, London, Paris, Moscow/StPete, probably a few I have missed. Australia, Singapore, Taiwan, HongKong. Half a rack (20U) in each location would more than cover most, though possibly the USA would require more.