I have previously developed a complete TCP/IP network stack in pure-hardware (no softcore within, FPGA e.g. microblaze) so have intimate knowledge of the project requirements. I suggest using an ENC28J60 (available on ebay for $2 USD) to interface the FPGA with the ethernet MAC layer.
I am also well versed in C and python and making a simple GUI will be very straight-forward.
Hope to hear from you,
Cheers,
Craig