I know this thread went waaaaaaay off topic from the OP but, is there a possibility to bring it back? Like in where does the community stand in regards to a solution? I take my hat off to the true developers keeping our cMP GPUs options current.
I have a couple threads on this very board with answers.
At the end of the day:
1. A GTX680 can do 4K at 30HZ out of the box and at 60Hz with a hack. (see my thread elsewhere, has "1984" in title)
2. As far as a particular card/display combo, you are currently best off finding someone else who has tried. Even with nMP the function of 4K is all over the map.