[EDIT: I TRIED AN HDMI->DISPLAYPORT ADAPTOR AND NOW EVERYTHING WORKS FINE. THIS IS THE ONE I GOT: http://www.amazon.com/Cable-Matters-Gold-Plated-DisplayPort-Adapter/dp/B00K0UDYLM. NOTE "HDMI NOT DETECTED" PROBLEM PERSISTS IF JUST USING HDMI]
I am a happy owner of a new CV1
I, too, have come across the error (Rift HDMI is Not Being Detected).
The funny thing is that reinstalling Nvidia drivers (365.19) fixes the issue for me - until I put the PC to sleep again or reboot. After that, again no HDMI detected. If I reinstall drivers, the HMD is again detected over HDMI and everything works wonders.
This is with a Skylake-based EVGA 980 SC (SLI, but with SLI disabled) system running Windows 10.
DXDiag attached / PCPartPicker view here: http://pcpartpicker.com/p/FNWZYJ
My main display is connected via DisplayPort and nothing is connected to the motherboard's HDMI input. Both the Rift and the main display are connected to the primary GPU (as SLI is disabled, the secondary GPU is effectively offline).