Las Vegas home prices rose for the eighth consecutive month in September, thanks to the valley’s tight housing supply and a record number of short sales. The median sales price of single-family homes last month was $140,000, up 1.4 percent from $138,000 in August and up 13.5 percent from September 2011, according to a report out today from the Greater Las Vegas Association of Realtors. The median sales price of condominiums and townhouses was $70,250, up 2.6 percent from $68,500 in August and up 24 percent from a year ago.