Can anyone verify that all 7 pcie slots work?  I've been working on this for several days.  I've got jumpers and the changed pcie settings in uefi.  I still get nothing but problems when I install more than 4 GPUs.  I'm runing Ubuntu 13.10, and it won't even boot half the time.
System browser in UEFI does recognize that I have a 5th card installed.

If someone has gotten this to work, please let us know exactly what you did:  Jumpers, UEFI settings, OS and drivers.

I haven't been able to mine much, but help us out and I'll certainly send some coins your way!