SMAAAASH!! Yoshi (as a texture) hasn't been released yet (though he is finished as of yesterday), but !!!
Currently, I've only had the character select screen portrait (seen above) replaced. The same texture is used on the victory screen, but if I want to replace the in-battle portrait as well, I'll have to do more work. I will do it later, and I'll also fix the fact that the "READY TO FIGHT" banner overlaps his eyes. I intend to make these for all the characters I stylize and some of the other texture hacks I make.
I feel successful. And, here's the full-sized version, which I'll use for other stuff: