I think you may be in error Al, at least with the extenders I linked to. The main issue is degradation of signal over distance. So the longer the cable the greater the chance for data to become unreadable. And the frequencies at which the PCIe 2.0 and 3.0 buses communicate, this problem will occur in a very short distance. The solution is to use shielded cable which is much more expensive. For a 12~24 inch extender with shielding, expect to pay $40~$100 for the privilege of ownership.
I think i figured out a way I can suspend a gpu below the Sabertooth motherboard. I top mounted the PSU, so I have room and the video contectors can point out the back where the bottom mount PSU would be. Might even modify the plate used to fill that PSU hole to help support the GPU.
Which ebayer did you buy from? Might as well go with a tested source.