I preordered an e6600 at clubit. All OEM version are out of stock as I checked but all retail version are in stock, but ship Aug 7. Fine print says "We are only taking orders for the number of processors that are in stock and in our warehouse."
As I just checked again, e6600 retail sold out. If you try to "pre-order", it will tell you no longer is available for pre-order. I assume they estimate how many will coming based on their order though Intel or distributor. Then use that to allow pre-order. So the pre-order is guaranteed, unlike other sellers.
Looking at many sellers I think OEM version might be available now but retail version need to wait for Aug 7. Since I prefer retail version and don't mind wait more if it is the only way to get retail. This is my best bet.
Maybe it's just my wishful thinking. Will know on Aug 7.