Southern Nevada has long been a place where architectural imagination runs wild (think volcano, pyramid and New York skyline), where would-be developers ignore the constraints of reality and hope their spectacular - if not fantasy-based - visions will take root and become tomorrow's icons. Now come two wildly contrasting visions of where Las Vegas-bound tourists can escape - one, a towering Strip hotel that would be the second-tallest building in the world and the other, an artists' village in the nearby desert that might best befit a world of unicorns and rainbows. As intriguing as each might be, they both...