I'm starting to approach a two (2) week rotation, but I'm also OCD enough that when I take my shoes off, I have minor panic attacks until shoe trees are inserted. My therapist says I'm getting better, though.
Merlot and dark brown are probably your best colour choices, given that you'd prefer to stay away from black and walnut. I personally have the McAllister in Merlot and the Strand in Dark Brown Burnished. They both go with a lot.
If you have the time and the inclination, check out the Allen Edmonds MTO Thread for additional ootions.