Since IEEE 802.11ac is a new thing heavily marketed by Intel, I wonder if it supports Wi-Fi Direct? My question is about standards overlap: is Wi-Fi Direct a subset of IEEE 802.11ac?
The short answer is no, it does not.
The 802.11 standard and it's amendments are developed and maintained by the IEEE. 802.11ac is "Very High Throughput" standard amendment.
Wi-Fi Direct is a standard developed by the Wi-Fi Alliance for which they also provide certification. This organization was originally formed to test and certify devices as adhering to certain aspects of the IEEE standards. This was done to provide a level of assurance to consumers that devices would be able to interoperate. It is a voluntary certification process and they can test and provide certification for a number of aspects of wireless.
So the longer answer is that Wi-Fi Direct is not a standard created or maintained by the IEEE and as such there are no current plans to incorporate it into any IEEE standard officially. If it were to be included in the future, it would become the basis for an amendment and go through the normal process any amendment goes through to get approved by the IEEE.