Looks like lots of fun.  I'm basically working on getting ready for the same thing.  I have 12 coming in about a month, and I've just recently committed to 7 more if all sellers come through. 

I was looking at how you did the PSU's.  Could you or would you recommend doing the same setup of 2x6 rack for PSU's in the front or over top of the D3's.  I just wonder how to do the same setup as you all stacked next to each other.  I guess once I get a few units in hand next week (hopefully) if deals come through then I can start playing Legos with them and build/stack them around lol.