Champs used to have tons with maaaaaad ballin' colors. Not sure if they still do. If you're in the States then I can't help you but chances are you'll have more luck. Oh, and try FootLocker if you just want black or white.
taller than a tall tee? are ya goin for like tall yet slim fitting so you dont look like a fat ass? jeff's technique sounds legit. but if you dont need it to be that skinny fitting a 5xl tall tee would probably do the trick.