Multi-Touch Patches Already Come To Wayland
Tiago Vignatti is the Intel developer that's part of Intel's Wayland team that's been working on multi-touch and he published his patch-set under a "RFC" (request for comments) state. The multi-touch support consists of evdev multi-touch support for direct devices, compositor multi-touch events notification, libtoytoolkit gesture recognizer for pinch and zoom, and a Cairo application example.
Tiago further comments, "The compositor doesn't keep any touch information and just forwards all to the picked surface i.e. client. That being said, multiple client support is not in place yet and I believe we would have to change the protocol a bit in a way that grabs are mapped for each touch point (currently we have only one grab per device). Also, the whole multitouch mechanism inside the compositor is not reliable in setting the correct pointer focus and picking the according surface. I rather not touch this side as well due we'll be changing the enter/leave events semantics a bit in input rework."
The patch series begins here on the Wayland development mailing list.