HELLO Sedor!
I like that idea; but so much so that it gave me another idea. The Cluster transport is x1; but Amfeltecs GPU splitters [~$200 (USD) -
http://amfeltec.com/products/flexible-x4-pci-express-4-way-splitter-gpu-oriented/ - are x4; so how about this:
Just create an L shaped GPU support rail that has a "L" lip with holes for screws to attach up to 4 GPU cards ; attach it to the motherboard side of the system and attach the GPUs to the back on the L-lip; attach the GPUs to the splitter cards [put the splitter card in the x8 or 16 slot] and now you've got 4-x4 GPUs externally spaced wide apart, in the open air, blowing hot air upward and externally feed, being blown air at their base from the fan cooling the PCIe bay; and three internal PCIe slots for non-GPUs (MPs support only 4 GPU processors - they're four slotted). GPUs would be much cooler too. It's now easier to connect them to a powerful external PSU. Metal railing would be dirt cheap; PSU and GPUs would cost what GPUs and PSU costs. What do you think about this? Content creators and Bitcoiners too would love this. All welcomed to pick up and run with this?