I am sure implementing compact TCP/IP stack and HTML server on the FPGA would not be that difficult
It's possible but takes engineering time, and FPGA resources away from the miner.
Better to use a $3-4 USB microcontroller IMO. Or a $10 ethernet MCU if you really, really need
a standalone device. But I prefer using a $50 Atom PC to connect USB FPGA miners to the net.
PCs are cheap and most people here have one running 24/7 anyway.
-rph