To what degree does Blender support PTex? I remember hearing about PTex a while back, and it was really exciting. IIRC, it was briefly, or maybe experimentally added to Blender, but the latest I can see of it is an experimental build of 2.73

Are there any plans to fully implement PTex?
Were significant technical problems discovered that made it unworthy of Blender?
What else is about it?
It is still supposed to be integrated, but later than 2.78.
Nicholas Bishop is working on it.