rmac: I am not so sure if tackling the disc size problem at the native access end is our best bet. As Druck said, we would need to replace Filecore for 1 TB HDs anyway, and then there are the hardware limitations (UDMA limit on IYONIX, no UDMA on A9 and Omega, PIO0 on RiscPC). For IYONIX and Omega, this would be theoretically solvable by writing a driver for one of the S-ATA PCI controllers, but it would be difficult to be able to boot from such a disc.
Maybe the best idea would be to leave the native HD access as it is and focus on NAS technology. We already have a very competent and fast NFS client, what we need is an optimized IP stack and an updated SMB client. With the IYONIX' gigabit networking, transfer rates of 40 MB/s should be possible, so it's in the same ballpark than native UDMA.
Of course, extending Fileswitch to handle files > 2GB would be necessary in any case.