With the help of Twitter, I learned that the corset is available at Frederick's but not in green (damn near every other color though). I quickly searched the net for advice about dyeing polyester, determined it could be done, and bought the corset. I added tights and gloves from a rocking site I just discovered, We Love Colors. Eventually I scrounged up a suitable green skirt at USA Dance Shoes. Whew.
The costume required more work than I thought, yet considering the end result, not so bad. The most time consuming part was dyeing the corset and skirt. I was incredibly happy with the shade of green my corset ended up. I followed the directions on the package and simmered it for about one and a half hours with frequent stirring. I put it right from the pot into the washer on cold and that seemed to set the dye.
The skirt required a little modifying. I ripped out a lot of sequins and cut off the bottom half. It was a little too pixie like. Since it was a lighter mint green, I threw that in the same pot of dye after the corset was finished.
Quick summary of supplies/sources:
Corset - Hollywood Dream, Frederick's.com (linked above)
Tights - Mint, Welovecolors.com
Skirt - Dance skirt from USAdanceshoes.com
Boots - search for green suede boots on Etsy (eBay had several too, just not my size)
Plastic ivy leaves - Michael's
Polyester dye - iDye Poly, Dharma Trading
Large enamel pot for dyeing