I have done exactly as Brad shows, albeit with 4 units... I have made a 4x2 screen array (2x2 eyefinity group) and can confirm that these units work very well under Eyefinity.
I wanted to call some attention to another notable difference between this and a DH2G...the signal power. Just as Brad had issue with a standard 3' cable...I had issues getting these going as well.
I had to feed (quality 22AWG) 25' DVI cables...that worked perfectly in UXGA res off of every passive or active adapter I had. These Zotacs wouldn't even THINK about it. I had NO interest in replacing 8x25' cables. I had to buy the venerable
Monoprice equalizers in order to get them to get the signal that far. At ~$30 each, 8 of them (and short HDMI jumpers) ended up being an extra $250ish that I was NOT happy about.
Granted, if you have short cable runs, this likely isn't a problem, but if your runs are long like mine, the deal might not be much better than a DH2G, which in my experience has powered DVI outputs and can deal with 25' cables fine, as well as the flexibility of the management software. Each Zotac (with the required equalizers/adapters) cost me ~$100ish, which is within the range of what DH2G can be picked up for on eBay (~$120ish).
Now I have a garbled mess of adapters:
Mini-Dp--------->Zotac--------->HDMI Jumper--------->Equalizer---------->HDMI-DVI Adapter----------->DVI Cable
.......................................--------->HDMI Jumper--------->Equalizer---------->HDMI-DVI Adapter----------->DVI Cable
When the DH2G would eliminate most all of that (granted, for HDMI instead of DVI, another adapter might be needed):
Mini-Dp--------->DH2G----------->DVI Cable
.......................................----------->DVI Cable
Moral of the story....if you have long cables, this *might* not be the droids you're looking for.