Better than expected actually considering zefir had reported seeing 750W draw for 8, my boards draw 110W less!  Getting ~390GH on my 8 boards drawing 640W on the dot from the wall with a Rosewill Lightning 1300W Gold PS.  Note the blindingly bright LEDs on the boards match well to the obnoxious Rosewill LEDS on the PSU  

Now the question becomes what kind of stability will I see? Currently if I stop/start cgminer its a crapshoot.  I used MinePeon and then did a git for the latest cg to 3.8.1 and got it all working just fine on a cold boot if I boot the raspbpi first and then power on the boards second.  However if I stop/start CG it all goes to heck - seems like the boards need to be "booted" fresh after CG is already running???

Seems like this will work fine until CG restarts    I wonder if the CANBUS has something to do with this, it was giving me issues in the beginning (random boards in the middle of the stack would never start hashing until I rebooted them).  I run two stacks of 4 just so I can contrast/compare behavior (hooked to same raspbpi).  Although I see the pi average load is pretty high (0.8+) ... top alone reports cgminer takes about a 0.4 load!

Has anyone confirmed the --avalon-fan option does indeed work?  I guess I should try.  The whole CANBUS thing makes it confusing, as I assume I am just getting the temp/core volts/etc from the first board only...  My boards show up as BTB, I saw perhaps a firmware update might fix some issues?  I don't know, still playing around, and information is sparse...