At the X.Org Board of Directors' meeting yesterday, it was confirmed about two projects already failing. "Unfortunately we had to fail two students, one that disappeared right after the program start and one who failed the mid-term evaluations." Sadly, this isn't too uncommon for these student open-source projects funded by Google.
This year's X.Org GSoC projects were very interesting and are listed here. One of the projects that failed was the the lightweight Qt Quick compositing window manager effort.
Of the GSoC projects, one of them that seem to be doing the best is the effort for exposing NVIDIA performance counters to user-space for the Nouveau driver.