It's still being crippled by the Zorro bus. An FPGA that could do a 500mhz 68060 could also emulate a PIV with much higher memory bandwidth. I don't have an A3000 but according to the internet, buster 11 hits 10mb/s with a PIV. DDR2 is orders of magnitude faster than that.
Throw in a floppy port that can use standard PC high density floppy drives, Ethernet, 96khz 32bit sound, sata, usb and I'm not sure there is much out of the A3000 that you'd still want to be using.
Yeah and then you'd need to re-write major chunks of the OS to support the new hardware, plus you'd want some of the things that modern OS's have, so that there'll be very little of OS 3 you'd still be using....wait a minute..wait a minute...I think we've gone down this path already....