Possible use for rack mounted pci expansion chassis

I have been searching through some of the posts here looking to see if anyone has ever done a build using a PCI expansion chassis to house the cards and then a separate server to drive them. I know this type of setup is popular for deep learning and protein folding calculations etc but curious if anyone has done this or if its possible for a hashcat build. 

Thinking of things like these: 

http://www.ebay.com/itm/Dell-PowerEdge-C...Sw5IJWfHVg

Or maybe two of these:

http://www.ebay.com/itm/NVidia-Tesla-S10...Swx2dYGoc0

It would probably take some finagling but might be doable and would be much cheaper than something like the SuperMicro SuperServer or a custom shops charge. Thoughts?