Audio-Video Alternative in Lilburn - my experience with these guys many years ago (before the 'Video' got attached to the name) was positive, and I am sure it is still under the same management. Literally a mom-and-pop shop (m and p work there every day) but with a decent staff. May still be heavily biased towards audio but give them a call and see how they do in answer to carefully chosen questions.
I was under the impression HiFi Buys in Roswell DOES have Martin Logan - they did the last time I was there, maybe a month ago. Bunch of morons though.
I am sure there are also several smaller shops. Go to Borders/Barnes and pick up a copy of the mag - I think it is called "Audio-Video Interiors". In the back of the mag they have listings of dealers who carry the equipment advertised in the mag. Not the full answer but it's a start.
Also try two other stores who I have not bought from yet but seem to have good inventory: Georgia Home Theater - Hwy 41 and 285, and Evolution Home Theater in Gwinnett. See Travis at GHT and Isaac at EHT. Not buds of mine but they were ok in my experience. YMMV.