LOL. I wish I had pictures on this computer, but I helped Kari make an awesome Dreamfinder costume a few years ago.
We found this hideous yellow suit at the Salvation Army store. It was pretty straight forward suit, just this awful yellow. Bought it for like 8 bucks (I guess they didn't think it would sell). Went to Home Depot and bought 3 cans of spray paint, and painted the entire suit blue. Didn't have the vest, so she kept it buttoned.
Went to a halloween shop and found a brown beard/mustache, sprayed it with orange hair spray. Just a little, and brushed it in, to give it a good color.
She managed to split the pants half way through the night, not much so it wasn't noticeable. But the outfit hit the trash can after that night. She can remember it by all the pictures we took.
A lot of people commented to her how cool her outfit was, and how well it turned out, even though it was completely last minute.
So even if you can't find purple velvet, a purple jacket would work just fine. People aren't going to be going up to your daughter to touch her costume. Sometimes it's the accents that really pull the costume together. Not just how exact you get it.