This is probably the best argument I've yet heard for the Mini or iMac over a Mac Pro. Get sh!t done slower, so you have more time to think. Think carefully about optimizing your work. It's also amusing that the Apple hardware defenders keep mentioning the "Pegasus". That just proves how limited fast external drive options are for Apple's disposable hardware - you have one brand a couple models to choose. Of course Thunderbolt storage has limited bandwidth...
It's the E5 v2 Xeon that's due for volume production in the 3rd quarter, I'm sure that's what he meant.
He's a video guy, he doesn't really know hardware tech any more than necessary to get his work done.
Just passing along what my buddy told me. I had to garble it a bit so he can't be indentified, otherwise, it's what he's been using at his studio.
3rd quarter 2013 is a long time though. Apple could easily kill the Mac Pro before then, especially if their computer sales keep tanking. I don't trust them to keep producing Macs more than 10 years or so.
I like the way you think. Such a Mac Pro design is entirely plausible and as long as it was designed to be accessable, it could work well. One caveat is cooling. If two 12 core Xeons are to be cooled quietly, space is required. If Apple starts getting cute with the cooling design (example: Powermac G4 Cube), then it's game over for the Mac Pro.