Nothing has changed on my machine, but I eventually gave up worrying about it.
I'm still running Catalyst 12.10. HDCP works on the Windows 8 desktop side according to tools that report on such things, and video apps that check HDCP work. But "Metro" video apps, including Hulu and Netflix, still yield the same errors (W8159 and PB4) as they did 2 months ago. Whether's an HDCP problem or not, something's failing in the DRM checks.
Hulu and Netflix still work in a web browser on my Win 8 PC. And they still work on my Mac mini. And they work on my Apple TV and Roku streaming media boxes. So I'm just waiting for someone to fix it.