(I'm totally just posting without reading through the thread so if I'm reiterating something someone has already said APOLOGIES IN ADVAAANCE)
A lot of people make the argument that uniforms combat a lot of the teasing centered around clothing between kids that come from families with different financial situations, but from my own experience, that isn't entirely true. It brings up a couple major issues for me:
One, how expensive and easily accessible are the uniforms? If your parents can't afford them (or even if they can only afford one "set" and you can't afford trips to the laundromat to accommodate that, or the water bill would get too high if you washed every day, and someone else happens to notice a pen mark from yesterday is still there today... situations like that, etc etc) then that's just more strain on your family and doesn't alleviate the bullying issue.
Two, what's the size range and how do the uniforms look on different body types? Because when you're the one in control of how you look, assuming budget's not the issue here, with the internet and everything nowadays it's a lot easier for people to find what's flattering on them. And for bigger kids, it's not gonna matter what they're wearing; teasing will come regardless. It's awful, but kids are awful, and uniforms don't change that fact. Also take into account that girls who are bustier might not be able to find a button-up that they can actually button up, depending. That can cause a bunch of problems as well.
And three, because it bears repeating... kids are awful. Bullying and teasing stops getting centered around clothes? Okay. So it picks up again with some new excuse instead. You can't eliminate all reasons for bullying, it's impossible. A better way to invest time, imo, would be putting the staff through training to combat the kind of stuff that goes on today specifically (ie cyberbullying, since so few teachers I've spoken to in my time have known what to really do about it), make sure counselors are active instead of shut away in their offices all the time (again, my experience here) and figure out some way to ensure that the staff in general aren't turning a blind eye to very blatant bull**** that goes on in their classrooms and their hallways.
Uniforms are cute and they work in theory, but I'm going off the issues that arose while moving from school to school as a kid (divorced parents, primary custody bounced between towns a lot) and things I've seen or heard from friends. Obviously there are many places where they work just fine but making the transition TO uniforms when you didn't previously have them, especially if you're on the poorer side? That's not fun.
I do like the idea of them, but I have my hangups. I think everyone gets the occasional teasing remark about their clothes once in a while so I'm not speaking from the perspective of someone who's been hardcore harassed over what I wore, but I do know enough to say that uniforms wouldn't have changed a thing, not in an of the five or six different districts I attended while growing up.