Samsung is getting ready to release a 4K monitor for around $700 capable of handling 60hz. Right now, you're looking at $2500-$3500 for a 4K screen capable of handling 60hz over TB2, so that will be something to look at when released.
That looks like it. It was mentioned on MacBreak Weekly this week, and they showed a photo of the monitor but didn't mention the specific model. The pic on that page is identical.