X Server 1.7 was supposed to be branched more than a month ago, but that never occurred, nor was there any beta release. In effect, X.Org 7.5 / X Server 1.7 is currently running eight weeks behind schedule right now, but still, it's unlikely to see this release come together in eight weeks from now. This is in fact just the latest delay, with X.Org 7.5 originally being scheduled for release back in April and then July.
With X Server 1.7 running behind schedule it's already been rejected from Ubuntu 9.10 and from OpenSuSE 11.2. It will likely be dropped from other distributions refreshing this fall too. Once release and picked up by the major distributions, X.Org 7.5 / X Server 1.7 will bring Multi-Pointer X and many other changes to the Linux desktop.
X.Org 7.4 was released in September of 2008 (after facing delays too), while this February there was the X Server 1.6 release available as an update. With the way things are currently going for X.Org 7.5, we will likely not see its release before late October or November, which will put about 13 or 14 months between these major releases.