Okay, let me make this perfectly clear: I'm not a brony. I respect people who are, but I stopped watching MLP after the first two episodes, simply because I didn't want to get caught up in some crazy internet fad, but I certainly don't hate the show. I'm only doing this to show that Yoshi isn't the only character who can be textured into a MLP.
The only problem is that even though the file size of my texture to turn Chicorita into Rarity is well below that of the original texture, Brawl seems to be crashing a lot before I get to see my texture in action. So I assume something went wrong with the texture. I'm posting the texture here. You can edit the texture however you like, as long as you can get it to work.
You can post this, but only if you put my name in the "Collaborated with" box. Deal?
I guess I should show you how it looks in BrawlBox. Here ya go: