I closed a deal with a supplier of a pair of W5590 engineering samples which are tweaked for overclocking beyond 3,33 GHz. The price is roughly half of the official price for W5590s. It is my intention to purchase a 2,26 GHz Nehalem mac pro and upgrade. I will be sharing the experience of this project in this thread. For now I have been told that there is one more pair of CPUs available. The seller isn't prepared to disclose his name but I can pass your email address to him if you PM it to me.