X Server 1.6 will ship with the revised DRI2 infrastructure, RandR 1.3, and X Input 2 (if it's ready in time) or X Input 1.5 with device properties. X Server 1.6 will also ship with Predictable Pointer Acceleration and other features.
Multi-Pointer X was already merged to master, but Keith Packard will be disabling MPX in X Server 1.6 if Xi2 isn't completed in time.
The new input thread work has also been requested as one of the X Server 1.6 features.
The X Server 1.6 release will come ahead of the X.Org 7.5 release, which he hopes will be ready by March of 2009. With that said, we're now looking at X Server 1.7 for X.Org 7.5. No release manager has volunteered at XDS 2008, but a release team may be formed to take the burden off a single person.
Keith Packard also mentioned during his XDS talk that he intends to close RandR 1.3 in roughly a month. He is hoping to have standard properties ready for this Resize and Rotate extension update, but that is dependent upon Matthias Hopf completing the work.
A tracker bug for X Server 1.6 and additional information should be available shortly.