Fine..show me someone convicted for being ugly. People do have gut feelings about testimony but that doesn't mean beauty has anything to do with it. Actually I think it's more probable that attractive people are more likely to be able to afford a good lawyer and that's the main thing.
Nobody gets convicted for being ugly... they get convicted because juries don't believe them and that they "didn't show remorse" the way a beautiful people shows remorse (whatever that really means). And who is believed less but someone who is ugly? When was the last time you believed Helen Thomas for instance? As for the beautiful person discount for better lawyers, sadly I never received that discount so I must be guilty. :-)
I've heard of several cases in which certain female jurors found either a defendant or his attorney highly attractive and refused to convict. I think this generally only results in a hung jury as not all women fall for this.