Tucson isn't too bad. Plenty of mixed neighborhoods. There are a few pockets of monoculture like the old barrios and the hyper-expensive foothills and one newer development that ended up being extremely white, protestant, and politically conservative. The only thing we can figure is that realtors are steering like minded folks into that development.
Things may have changed in the decade since I left but when I lived in Lexington, KY you could draw two lines across the city to cut out a pie wedge and separate 95% of the white folk from 95% of the black folk.