Like Ventus said, the Zelda franchise isn't
big enough for a game like this to be possible. I don't even think that Nintendo would ever desire to spend the time on developing it, because it just isn't worth it.
Let's take Pokemon for example. There are so many Pokemon (I would argue that 649 is a bit too much) that you can have something like a Pokemon battle tournament. I think this has already been put into the games themselves, as well as made into some spinoffs. Pokemon brawls are worth Nintendo's time.
Now, let's look at Metroid. There are
nowhere near enough
[good] characters in Metroid for Nintendo to even
think about creating a whole separate game in which you can have the characters battle one another. It would not be worth their time, and neither would a whole Zelda battle tourney game be (and Mario would be kinda dumb- the characters don't seem like they're into battling, it's more like go-karting, partying and tennis for them
)
However, I would love to play a game like this. It kinda reminds me of Tekken/Soul Calibur mashed up with Super Smash Brothers.
Maybe, as the series develops further, this could be possible.