Regional DNA Studies

I received my Ancestry DNA kit this last week and took the test, mailed it and activated it on Ancestry's website on the 13th of this month.  In the mean time I have been trying to keep busy and not think about it too much.  I know....Good Luck with that.  In an earlier post to my blog I gave it my best guess on what I think my ethnic breakdown will be.  I am really looking forward to comparing the results with my tree.  Barring some kind of crazy find in the one line that I don't have back further than my Gr Gr grandfather I am pretty much colonial American with those lines coming out of Maryland and Virginia in the 1600 & 1700s.  By 1800s most of my lines were in Tennessee, USA with many in the area just prior to the formation of the state in 1796.  This has got me thinking about DNA research for areas.  I know there is a tool where you can take your DNA results and compare surnames but is there a tool available to the public where you can compare areas of the USA during more recent times that would be helpful to those looking for adoptions and non paternal events within the last 200 or so years.  Using both the Location & Surname together could help.  Something similar to a surname study but for a specific region.  If so I would be interested in a Colonial American one and also Early TN Settlers. Just some thoughts.