I have ROM files for both Winning Post 1 and 2 for SNES (Japanese version, of course) :bleh:
I found them in a regrettable place (littered with porn), but they work nonetheless.
So, to avoid giving you the direct link, I just went to Google and searched for
'Winning Post ROMS', and the first site had it. Warning, Adult Content. Sorry, that's the only place I could find it. If you'd like, I can try to upload the roms somewhere, but that might prove troublesome.
Oh, and I don't think there is a Winning Post 8 yet
, 'Winning Post 6' and 'Winning Post Box' are the latest. (There's one for GBA too).