you can pull the superdrive and expose the sata connector and turn it into an esata and then run that to a 4-5 drive estata enclosure externally... the new lion os has the option to be a server or a workstation... your choice for $29...
Stick with Firewire on the Mac if you don't go this route... WD makes a 2 and a 4 drive external drop in drive setup for firewire.
Stick with Firewire on the Mac if you don't go this route... WD makes a 2 and a 4 drive external drop in drive setup for firewire.