I saw someone post that Asus has on the road map a 1440p IPS screen with gsync on their roadmap. Alas I can't now find the link so it should be treated as hearsay of a rumour (ie worth like nothing) but if its true that is good news.
The people that won the gsync kits on pcper.com have been reporting in on the experience of upgrade and what its like. One of them likened it to feeling of going to 60->120hz. They said it was about 50% more of that improvement again on top of the improvement already received from going to 120hz screen.
They all commented on how washed out the Asus screen is though, and at £441 I will not be buying an otherwise terrible monitor. If it was a bit more like the price Nvidia first described I would be more interested, but the markup is more than twice that expected.