The West Bank's first Palestinian-designed planned city offers a window into the promises and perils of the current situation in the Middle East. But will it be a novelty, or a game-changer? The sole outlet to Rawabi sits off a dizzying two-lane highway flanked by round, scraggly hills. In this part of the West Bank, just north of where the Jerusalem suburbs thin into a dry, granite-gray wilderness, the mountains seem to aid in the illusion that Israeli and Palestinian spheres of authority can remain perfectly, even harmoniously separate. Arabs use the road to get to the Palestinian-controlled cities of Bir Zeit and Ramallah; for Jewish