The X58 is inherented limited to only 36 PCI-E lanes, and I'm not sure how you could truly expand that, short of reengineering the chipset itself. I expect that if there were multiple devices NOT working together, the NF200 could give each one 16 lanes as needed, as long as they didn't all need the lanes at the same time.
Incidentally, if you check out the
Evga X58 board review that just put up, it's got a section testing out the effects of 8x and 16x lane combinations. Conclusion: difference = pretty much squat. So even if the NF200 wasn't gimped in application, there doesn't seem to be room for improvement in the first place. And by the time there is, PCI-E gen 3 will probably be showing its head.
Edit:
'd. You gonna make a thread for that board review?