Clone part of a layout in Pcbnew.

1. Organize the subschemas to be cloned in hierarchical sheets. Annotate them so that each sheet's components have reference ids starting with a different hundred. Export netlist.
2. Import netlist into Pcbnew. Draw edge cuts. Place and route the components that will not be cloned. Also lay out the lowest-numbered subschema as a template. Surround it with a filled zone in Cmts.User layer (blue box). Tracks must be completely inside the zone.
3. Save EXAMPLE_NAME.kicad_pcb. Edit your layout_cloner.py to match your circuit (instructions inside the file). Run it to produce EXAMPLE_NAME_cloned.kicad_pcb file. Open it in Pcbnew. The ratsnest may be wrong; toggle it off and on to fix.
4. Clean up the edges of the patterned components. Try to keep this step as short as possible, because this work will be lost if/when you revisit Step 2.

Open Terminal and run:

python layout_cloner.py

Your system Python probably doesn't have dependency pcbnew. Easiest to use KiCad's bundled Python, PyAlaMode.

Edit layout_cloner.py again to make the paths absolute:

inputBoardFile = r'C:\REPLACE_WITH_PATH_TO_YOUR\EXAMPLE_NAME.kicad_pcb'
outputBoardFile = r'C:\REPLACE_WITH_PATH_TO_YOUR\EXAMPLE_NAME_cloned.kicad_pcb'

In Pcbnew, go to Tools > Scripting Console. Paste this command and press Enter.

execfile(r'C:\REPLACE_WITH_PATH_TO_YOUR\layout_cloner.py')

If you have non-ASCII characters in your path, use this command (note double backslashes). Paste and press Enter twice.

with open(u'C:\\RÉPLACE_WÍTH_PÁTH_TO_YǪÚR\\layout_cloner.py') as f: exec(f.read())