External RAID for MAC server

I have a client that wants to add RAID-5 to a G4 MAC server. We need to go with an external enclosure and want to do SCSI instead of firewire for the added performance. Has anyone seen a product to cover this? Will a standard Adaptec RAID controller work properly in a MAC? I?ve never tried it.

Assuming there is no black box solution, does anyone know where I can order external RAID enclosures with power supplies, SCSI external connection to internal connection adapter, etc?

Thanks forthe help.