I've never heard of Anyone having a wedding at Shades of Green, and I really don't think that is a possibility. However, if you still want to get married on Disney property, but want to keep the cost down, Try looking into the Swan and Dolphin Resort. you can get married there on the Cresent Terrace, and I think there is another location there too, but I'm not sure what it is called. This is a great option for those brides who want to invite more guests than what Disney allows for an intimate ceremony, but doesn't want to up their budget all that much.
You'll want to check out justmarry.com I've heard of several Swan Dolphin brides who've said they were very happy with their wedding there. Good luck!