From doing some more investigation; it seems that it's available via TPUG (Toronto PET Users Group)...
Search this Amiga catalogue .PDF for "Palcon":
https://www.tpug.ca/tpug-media/catal...g%20300dpi.pdf
Code:
(A)TBO - September 91
---------------------
PALCON - switches 1 MB Fatter
Agnes systems between NTSC
and PAL format screens (CLI)
You can order the "
TPUG Library CD" here I guess as I can't find the disk anywhere:
https://www.tpug.ca/2009/12/tpug-library-cd-available/