Its Columbus Day weekend Oct 9 - 12. Also, Taste of Atlanta is happening the 10 & 11 at Technology Square in Midtown Atlanta. Would it be possible to get a few cars together so soon on such short notice? Probably not. But worth a try.
Found this site too
http://www.atlantacarshows.org/
If you're a member at SmartUSA Insider, just use the same info from SUI to sign in at Atlanta Car Shows. They seem to have a few events happening this month. At least 3 or so. And it looks pretty active with cars of all varieties.
And of course the Atlanta Journal Constitution's annual car show:
http://www.ajcautoshow.com/ In 2010 its March 20 -28