By Alexandria Sage and Paul Lienert LAS VEGAS (Reuters) – Electric vehicle start-up Faraday Future showed off in Las Vegas on Tuesday a prototype of a vehicle set for production next year as the China-backed company strives to win credibility in the crowded sector and weather its funding challenges. The "FF 91", described by its designer Richard Kim as "weird-pretty", is a luxury electric SUV Faraday executives say will be the most technologically advanced on the market when it goes into production in early 2018. "You're about to witness day one of a new era of mobility," said Nick Sampson, senior vice president of engineering and research and development.