I hope the next gen GPU (9xxx), in its multi-monitor hardware/software technical update, can provide native support for HDMI-based HD3D Eyefinity configurations, as well as DP configurations. Most new technology commercial displays are favoring HDMI, not DP...
On a somewhat related topic, I have encountered a display initialization problem when connecting 6 GB GHz 7970 to Sony's new 4K UHDTV (XBR65X900A) via HDMI. Note that the 7970 is one of the few industry GPU cards capable of supporting the X900A's full-frame 1080p (passive) 3D at 30 fps, as well as the full 4K 2D display. I have contacted both AMD and Sony tech support, but the X900A remains unable to accept the 7970's data.
Aug 13 update: Sony released firmware update for X900A that resolved display problem with 7970. Great, fast work by Sony! 4K 2D and full-frame 1080p 3D run at 30 fps with the 7970 - the UHDTV looks great.