What all SFP transceiver seem to provide is the modulation of a differential signal on some medium and the demodulation from that medium to a differential signal. Most SFP tranceiver are meant to interface to some optical fiber, but there also are some that provide yet another RJ-45 with Ethernet.

I'm interested in the optical ones. Optical fibers have a number of advantages over metal wires, which I already discussed in the projects description. Therefore they are interesting for all kinds of projects. A great example is OneTesla. They use fiber optic transmitters, cable and receivers to isolate the breaker controller from the high voltage of the tesla coil. One could also think of having an isolated USB line to put a SDR dongle on the roof without worrying that a lightning strike might fry your computer.

Basically right know I'm looking for excuses to build this little side project :D

But I'm not the only one building silly breakout bords. Even Xilinx is doing it. The Status right now is that I'm waiting for the PCBs and parts from taobao...