yes, they can technically do it, but they can't take up much room at all (currently the max is 40mb, but nintendo could raise that some).
i'm pretty much sure the punch-out prize thing is about 200-300 blocks big (so, it probably couldn't be much bigger), and it only lets you fight against ONE charecter.
come try out the computer game i've been working on for my high school senior project, titled sling ball. http://vgchartz.com/forum/thread.php?id=76669&page=1
you can view a few screenshots from the game in my photo album here; http://www.vgchartz.com/photos/album.php?album=2312
yes, this is vonboy's alt account. i can't log into my original account, and i'm not sure if i will ever be able to.
Proud Member of the Official Yoshi Fan Club!.







