Methinks I need to take a closer look at this FPGA Arcade thingy. I haven't been following it at all - what you're describing sounds pretty darn cool! Is there a good web resource to learn more about its Amiga features?
Check out Mike's site:
http://www.fpgaarcade.com/Especially the forum where there's lots of discussion on the various cores under development.
Here's a pic of the FPGA board with the prototype 68060 board fitted on top.
http://amigatronics.files.wordpress.com/2012/05/060-daughter-board.gifYou can see the CPU, USB ports, extra RAM, clock, optical audio out, micro SD card (which can be used as a "real" Amiga formatted hard drive rather than using HDF files on the main board's SD card), and Ethernet port.
So in short you get the following:
Main board: Various cores running different systems/arcade games. Amiga core to feature: Soft 68000/020 Core, 64MB RAM (user configured between Chip/Fast/etc), OCS/ECS and AGA chipset (with P98 RTG), SD card to hold ADF, HDF, Kickstart and core files, PS-2 ports for mouse & keyboard (optional USB ports for USB mouse and keyboard only), DVI video out (optional S-video and composite), stereo audio out, 2 x 9pin joystick ports, JTAG connector, expansion port (for daughterboard), Serial port, micro USB port for flash updates.
Daughterboard adds following (subject to change): Real 68060 CPU, extra 128 MB RAM, Micro SD card slot (as hard drive), optical audio out, real time clock, USB, Ethernet.
While the daughterboard is being developed with the Amiga core in mind (and anyone can build their own cards for the slot), I see no reason why an old Mac core or Atari ST core couldn't make use of it either.