How this hasn't been promoted to front page news is beyond me!
For those of you who haven't checked out the source code...
It uses the AROS Rom as the basis for the emulation but can use the proprietary roms if available for better compatibility.
Almost all instruction sets have been emulated via software and all hardware is created modularly to allow for different amiga specs to be used, as well as the addition of new hardware as well as the removal of unneccessary hardware (for example a MOD player would not need the video ports).
I am guessing that everyone is waiting for somebody to port Workbench / Wanderer?