Interesting. I only skimmed through it all, but only 2x760Watt PSU's for all those drives ?? I guess that's ok, 20-25watts per drive roughly would leave enough for the rest.
And a single boot drive?? I would at least RAID0 that. Seems like a huge point of failure, though I guess it's pretty simple to swap out if it fails as they are likely standard images.
Bok