If you're doing HardCopy-style structured ASICs, in theory you could put a fastish 32-bit processor and Ethernet MAC on the ASIC itself. It'd probably only take up a smallish proportion of the chip and you'd just need boot flash and Ethernet PHY chips externally. Not sure how much sense this would make though.
Depending on expense, i'd look at adding a small XMOS processor to the board. It being transputer in essence was designed to talk other chips like ASICs and other XMOS. The ASIC is left doing its special magic, the XMOS handles everything else (including block submits etc.) and can be easily connected up into massive rigs as required.