Astro Gallery of Gems is a source for green, blue, and orange
calcite rough. They may have small cabs or can cut them for you. They
have been around for a long time, so it's possible they have what you
need. They have a store on Ebay. If I had any of this stuff, I would
cut a few cabochons for you. I'm sorry that I don't.
eBay link removed - Sorry no eBay auctions on Orchid