So I just replaced the motherboard on it (Dual Xeons annoy me with their 8 screws under the heatsinks... why can't I remove the board with the CPU's/Heatsinks still attached is beyond me!)
So after all this we have replaced:
Motherboard, SCSI Card + ECC RAM, Backplane, SCSI Drives, and a SCSI cable...
Finally things are on the up and up! The SCSI Array build process was twice as fast as before, so obviously something went better (perhaps it was getting Intel Certified ECC RAM for the SRCU32 SCSI RAID controller that made the difference) [cool].
Now... to Ghost from the Temporary SATA installation back to the RAID 5.