i dont know if this should go under protos, foreighn releases, or what-
Strike It! ....by Bit Corp
PG-904 existed boxed (at least in mock up form). shown in a flyer from bit corp with all the other bit releases for colecovision (with boxes!).
homebrew:
Lode Runner ... Steve Begin
this is a port of the Sega SG-1000 title. extremely limited amount produced because of copyright infringement fears. approximetely 10 exist.