Seven new Vegas residencies are headed to the desert this summer and fall, while four current performers have extended their stays and one performer has canceled. Plus, there are rumors of the next big performer to call the spear home, and we’re discussing all of them this week in gambling! Back in early January, we reported on all the new concerts, comedies, and residencies headed for Sin City this year. And while that video is still available and mostly accurate, things move so quickly that it’s already time for an update. While four performers have extended their stays, no. While…