VGFacts

Here is a Youtube Video showing the ending: http://www.youtube.com/watch?v=HMG_V1yELjo
(Notice that the description in the video shows he used codes to obtain the ending

Megaman Knowledge Base also states it has no ending and does in its references point to the Youtube video as listed above: http://megaman.wikia.com/wiki/Mega_Man's_Soccer

So there is an ending, but it is hidden in the code and has to be pieced together. Nice find.