I finally got it built today and installed Win 7 on the 64gb SSD. I figured the 64gb would be big enough for the OS and 2x wow folders. I totally forgot that you need as much free drive space as you have memory so I ended up with only enough room for 1 wow folder. I put the folder that runs all 9 alts on the ssd and put the main folder on a sata hdd.

With "ultra" settings with only the main wow up I was able to run through Dalaran at around 30 fps. It was only using the 1st and 2nd core though. I'm not sure if its possible to run on all 4. That frame rate was kind of disappointing. It was stable at 60 fps anywhere else I went.

Then I loaded up all 10 wows and set cpu affinity to main on 1 and 3 of alts on each of the others. Sent summons to all of them from Dalaran and put them all on follow. None of them dropped while running around but it looked like it was real close to happening. The frame rate was kind of finicky at around 10-15 fps. This was using ultra on the main and low on the alts.

Odd thing is that I was only using 7 GB or ram while doing this. I figured it would be much higher. The CPU is the low point as some have guessed. It was running at near 100%

Overall I'm satisfied with how it runs. I can deal with some low frame rates in places like dalaran or wintergrasp. Everywhere else it runs very smooth.

If anyone is contemplating making a system for 10+ box I suggest 2 CPUs and 12gb ram which should do it.