There was one PCI card which had 100MB/s IDE/ATA, Firewire and USB bundled: the Sonnet Tempo Trio. Good luck finding one these days though, particularly the Mac compatible one.
One note with adding a faster storage controller (PATA / ATA) - have a think about how you're going to route cabling from the card to the drive bay. That may well be a little trickier in the AIO than in the desktop/tower G3.
One note with adding a faster storage controller (PATA / ATA) - have a think about how you're going to route cabling from the card to the drive bay. That may well be a little trickier in the AIO than in the desktop/tower G3.