Just a few suggestions, this doesn't neccessarily pertain to the rules, but it may help with the tourney.
Not sure about "no health items," but if you feel its neccessary, I don't think its a problem.
15 stock seems to be a little too many. This might result in a 20 minute brawl if the two players are too closely matched. Though later in my suggestions this might be better.
One map per each round is very good. Maybe start out with maps that don't change for the first couple rounds, and then progressively make the maps harder in terms of skill needed to move about. i.e. first round starts at battlefield, 2nd round a little harder, maybe pokemon stadium near the top of difficulty? I'm not sure, since I've barely played brawl, but I have played Melee.
And it seems like there's too many people to get a true round-robin tourney, so maybe do a double-elimination tourney? A championship bracket where everyone starts and a consolation bracket as a last chance for those who lose a match. This in my opinion is better that a single-elimination bracket, because sometimes you get unlucky, and second-chances help skill outweigh luck.
The rules are very good the way they are. Just these slight improvements may help with the organization of the tourney and so forth.
