Hi Christian, check out the SOLAROS.com website. It's the home of the Atlanta / North GA Land Rover group of which I am the membership chairman. You can source a wing for your new rig from George Laird at RoversDownSouth.com. It'll come primed or white, you can have painted or paint it yourself and install it yourself too.
If you'd rather a professional do it, I am certain there are many reputable autobody places in Atlanta. If you have the part and need it painted and installed, just call the North Point LR dealer (they are all Hennessy owned so pick one you like, I like NP) and ask for their input on a body shop. You can also contact Bill Saks at Bear Valley Land Rovers in Roswell. He'd prefer to sell you a damage free red 90 himself, but will gladly direct you to a reputable bodyshop if you ask.
If you are in the area this wednesday night at 7pm, come by the Logan's Road House on Mansell Road (just off Exit 8 GA400) for our monthly meeting. There'll be plenty of 90 junkies in the room to give you all kinds of unsolicited advice.
Anything is possible, with the right tools...