My story so far:
Nov 2: Bought a new Mac mini i5 (late 2012) to replace a Mac mini (Mid 2011) with Intel 3000 Graphics. Setup:
Mac mini (2012) w Intel HD Graphics 4000 -> HDMI -> Yamaha receiver RX-A810 -> HDMI -> Samsung TV UE55D8005
Random videoblackouts (interval 2 - 120 seconds) and sometimes purple screen and "color noise", sometimes total blackouts.
The previous mini (Mid 2011) worked flawlessly in this exact same setup.
Nov 14: I replaced the mini i5 with a new mini i7 (with the same Intel 4000 Graphics). The EXACT same problem.
Dec 1: I tried the beta upgrade 10.8.3 build 12D32. The EXACT same problem.
Dec 11: I installed the EFI 1.7 upgrade. The EXACT same problem.
Dec 11: I tried the beta upgrade 10.8.3 build 12D38. The EXACT same problem.
I really don´t care about this problem any more. This Mac mini is exclusively used as a home theater player and I got good service and support from Apple (except my problem is not yet solved). I will now use an older mini 2011 instead with discrete graphics (and better graphics performance).
I will probably never know who is to blame: Intel, Apple, Samsung or Yamaha. HDMI is really "a bag of hurt" (as Steve would say) and all the problems with HDMI as HDCP, signalling, sync, UDID, etc will probably never be solved.