Did some searches and nothing came up. There’s lots of .17 cal variants out there, but haven’t heard anything about 12-14 cals.
the old Qual-Cart site is the only reference I have ever found either.
that site also listed other really bizarre wildcats:
for example — the 32 S & W Short necked down to 7mm
for the life of me, I have no Earthly idea what such a pipsqueak cartridge could be used for.