Any of the boards on this page will support your cpu. Only a couple of them have isa slots though. Yeah, they're getting tougher to find
Forward thinking, I would consider buying a PCI based SCSI card. That way you dont have a ISA slot in your system that you wont be using when you outgrow your scanner. I've considered this, but I need an excuse to build a nwe box. >grin<
Plus, you could always use the new card for your SCSI drives if you ever felt inclined to purchase some.
You could also look around for some boards that has SCSI on board already. Then, you dont even have to use up a PCI slot.