I don't see if they found out the pinouts for the SFP connectors on the back. If those were documented, and the PCI-e lanes were documented, I could see someone having some real fun with these building some bespoke fiber networking gear.

SFP transceivers are just that- transceivers, they will spit out what you put in, so you could even build some interesting bespoke fiber optic signaling gear with these, and a PCIe backplane, or just solo.