Are the adapters from dual row header to card edge wtill available?
(They were used to connect a 3.5" drive to a 5.25" drive cable)
Could you put two of those back to back connected by a header?
In the late 1970's in the TRS80 world, there were MALE 34 pin card edge
ribbon cable connectors! with gold plated fingers! (used on a short
extension for drives in enclosures, and to convert expansion interface
connections to gold-plated to withstand corrosion and lots of connections)