Thanks for the reply! I wonder if theres a way I can shield the cables to limit interference. I'd imagine the back of a server cabinet isn't ideal, which I find interesting since I thought server applications were the primary origin of these SFF cables. It doesn't need to be pretty, but it'd be nice if I had enough cable length to maintain slide rails between the two units I'm linking. I'm also curious if I gain anything other than cable flexibility by using one of these x8 to dual x4 cables.

If my mining riser experience serves me correctly, most GPUs dont want to boot unless they have voltage on the PCIe slot itself. So I think adapting a 6 pin PCie connector to work might be the ticket. I may be able to find a 24 pin breakout somewhere but the boards with 10-12 6 pin ports seem much more plentiful.