Neville a couple of questions?... What are you going to use that slot for. What are you going to put in it that actually uses the bandwidth? What 64bit PCI device do you have?
About the only thing I know of would be a PCI RAID Controller. using 64bit PCI, almost certainly it's going to be SCSI, almost certainly several hundred dollars.
No use for the avg. joe. That's why you don't see them on Consumer level Motherboards. Only Server Boards. It adds to the cost and complexity of the MB and is petty useless for 99% of the buyers. I'd rather not pay an inflated price for a feature I may never use.
If they want to use all that Bandwidth on the NForce2 maybe they should try embedding a Ti4600 core instead of that hoaky MX variant they use.
just a reality check...
"If Wishes were Fishes, No Man would go Hungry"