On 11/29/2016 01:47 PM, Peter Coghlan wrote:
  A single chip plus tranceivers solution would be ideal
but I couldn't see it
 being that easy :-) 
I have a single chip plus transceivers solution but my single chip is a
Xilinx Artix 7 FPGA.  Maybe that's cheating but it does implement
register reads and writes, interrupt cycles, bus master operations, and
memory reads and writes in that single chip.  :-)