These twin cities, separated by 30 miles of suburbs, may be the oddest couple of all in a state of odd couples. Dallas is glitzy and ritzy, a swelling, modernistic business metropolis whose inhabitants go to bed early and to church on Sunday. Fort Worth, sneered at as "Cowtown" by its neighbors, lives in the shadow of its wild history as a rip-roaring cowboy town, a place of gunfights and cattle drives -- even though its cultural establishment is superior to Dallas's and it has seen a downtown rebirth in recent years. In Fort Worth that fellow in the faded jeans and cowboy hat could well be the president of the bank. In Dallas, people tend to be a bit more formal.