I've made four different backplanes, two are buffered and replicas of the original Acorn 8-Slot and 12-Slot Backplanes which I have, the 10-Slot unbuffered backplane is intended for a System 5 whilst the 14-Slot Backplane can be used for an even bigger System 5 or my combined FileStore/Econet Clock and Bridge.
I haven't found an original Acorn schematic for the Backplane, there is a little information in the System 2 Technical Manual.
My 8-Slot Backplane is a good copy of the original Acorn 8-Slot Backplane, this was a single sided PCB and only tracked the Side A connections. I have also tracked side-B on the top side of the PCB. The 12-Slot Backplane is simply a stretched version of the 8-Slot.
The 10-Slot and 14-Slot Unbuffered Backplanes simply tracks both A and B sides across all 10-Slots, it is intended for systems which have a buffered Address Bus.
Schematics
Bill Of Materials
Blank Backplane 8-Slot Buffered
Blank Backplane 12-Slot Buffered
Blank Backplane 10-Slot Unbuffered
Blank Backplane 14-Slot Unbuffered
Photo to follow