ATI's solution is Havok. It is mostly (if not at all) implemented in software and is in the Catalyst drivers. I do not think NVIDIA have anything similar to Eyefinity at the moment although i am pretty sure they will come up with something in the near future. But at the moment they have more important problems to solve; get an actual card on the market.. then improve it.
From the leaked info they won't even be in the same universe, the GTX 470 is probably between a 5850 & 5870, so the 5970 will probably be twice the performance.
However all of this is based on leaked info, and can change.
If you dont mind me butting in here and saying "So what if the 470 GTX is faster than the HD 5970?" I mean why be so worried about it being any faster? You already have two 5970s so why not just enjoy them?