I've recently acquired a small support contract to help build and troubleshoot issues for a European-based media company. They've built their own simple CDN with servers around Europe to deliver content. I've built and deployed two new Squid-2.7 servers for them which handle their current summer holiday load (20-30mbit at peak) with absolutely no trouble whatsoever.
Based on their existing servers which I'm apparently helping replace, they predict the servers will each peak above 150mbit/sec once the holiday period is over and everyone is back at work. I'm looking forward to it. I've got a few configuration tricks up my sleeve to optimise their setup to dramatically reduce the CPU consumed without any code or system changes. Stay tuned..