It seems Sin City cannot get enough when it comes to professional sports. Now there are rumors of a Las Vegas NBA arena set to be built near the Rio. If true, that would be a step toward getting an NBA franchise, either by relocation or (more likely) league expansion in the near future. But can we trust these rumors? I mean, it’s not like they haven’t been circulating for years. Sources at some reliable blogs are sharing that the Oak View Group is moving forward with plans for this Las Vegas NBA. Previously, they had announced a huge, multibillion…