I have one that was purchased years ago but has never been worn (in fact the tags are still attached @_@). I got it at a dance store. It is an adult small, and the brand is 'Star Styled'. I paid $37, but will let it go for $25 because there is a small run in the fabric at the back of the neck (it got caught on a piece of plastic boning that I had it stored next to >_<).
The run is approximately 1.5-2 inches long. It could easily be stitched-up, and I doubt that anyone would ever notice the repair (especially if you're wearing a long wig or have long hair). The suit zips-up the back, has a mock turtleneck, and long sleeves.
Please let me know if you are interested and I will take some photos!