I have the same problem.
I will try this:
"PCI Express 1X Male To PCI-E 16X Female Riser Ribbon Extender Cable Adapter"
http://www.ebay.com/itm/PCI-Express-1X-Male-To-PCI-E-16X-Female-Riser-Ribbon-Extender-Cable-Adapter-/182073676051?hash=item2a646fd113:g:xhgAAOSwgApW~QfU
Then add a simple PCIX lame card just for UNRAID. Cold it work? Anyone tryed? Because I have 3 free PCIx x1 slots.
Thanks!