Costume Design Process Starts...

I have finally started thinking about the specifics for the designs for the characters in Dark of the Moon. I did not expect to find this much difficulty in finding design ideas for the characters here since I have been thinking about this show for so long (I have been planning on doing the show since I STARTED my course work for grad school at CWU). My biggest issue is with the witches. I cannot find a balance between something I like and something that is appropriate/workable for the audience and students that will be in the show.
I want the audience to see the show through the eyes of John, the witch boy. For that reason, I want the witches to feel like they are the norm - that the people in the town need to be the one's that feel out of place. The only people that can seem at all "normal" in the sight of John should be Barbra and the Conjur Man & Woman. Barbra because she is the one that John loves; and the Conjur Man & Woman because they are the only characters that cross both planes and can feel semi-normal in both worlds.
The problem that I am having is that (especially with the witches) all of my research leads me back to witches that are more than half-naked. The historical plates and drawings that I come across are all of witches performing ceremonies in the full nude - particularly for the back-woods southern feel that I beleive that the show requires. I have seen a few production shots from other showings of Dark of the Moon, mostly college productions, that have witches in pretty much nothing but a unitard and some tulle - showing everything that they have (and in some cases accentuating those items). I need to find a way to combine the elements that I like while at the same time making it comfortable for my actors and accessible to my audiences. We are already doing a show that is going to push some boundaries and buttons, but I still want the show's message and themes to be accessible to my audiences and the students that participate.
I will just have to keep playing with some renderings and drawings until I find something that I like. I think I am going to try to get a hold of an Undergrad friend of mine that is a costume designer in Houston. I have talked with her about the show before (she loves it) and perhaps I can bounce some ideas off of her to see what we can come up with.