Random request.
How about Ike's older, beefier form from Fire Emblem: Radiant Dawn? Here's a picture:
Not the greatest picture, and I can't really find any screenshots of him (he's not a main character in Radiant Dawn) but you can see the model for him in this video starting around 2:45.
I just think it would be badass, and he'd certainly look deserving of the power he wields in Brawl
And if it would be like a real quick job... A Roy with awesome hair that only takes up one slot would be great, buuuut I'm thinking you wouldn't be motivated to do that due to the other models out there. I like the one that uses the Golden Sun hair, but that requires a PSA or a PAC that modifies all costumes or something, and the more recent vertex hack one's hair look all pointy and unnatural. Not to mention the bulgy forearms that still have the gloves on them but are just textured to look like skin.
Oh, and I'd love to see a good Snake from Twin Snakes as well. The original MGS and its remake is one of my favorite games of all time. Plus I just love the vest he wears.