Unless you're looking at xeon/server class boards you're hard-pressed for much of a selection. ATA and Serial ATA has pretty much taken over what SCSI had before, expecially with ATA RAID being available. Can I ask why you're looking for SCSI onboard?
If you're looking for what SCSI brings, SATA and ATA RAID will do as good a job for cheaper. If you have a SCSI drive and you want to use it with a new system, I'd suggest an add-on PCI card - its cheaper and it gives you more flexibility with your mobo purchase.