It's very true that nVidia can adopt whatever memory standard they like.
See the problem here is that they dont make memory. so they have to find another partner that makes memory. This partner will also want to sell DD2 to use in mombos as that has a higher rate of volume (ie makes them more money) then showing up in one high end video card. I find it very hard to believe that the mem compaines would even consider a non-standard mem support. Too costly to have 2 types of memory parts (one to fit nV standards, one to fit Jedec). However if nV is close enough to jedec standars then its more likely to happen.....