Las Vegas home prices are rising at one of the fastest rates nationally, and builders are selling the most homes in years. But by almost any measure, the market remains a long way from the peaks of the bubble years last decade. Builders sold 9,400 homes last year, the highest tally in almost a decade but far below the record of almost 39,000 in 2005. The heated market has shown some signs of cracks, and the tally of closings could further soften next year.