Honestly...I actually don't hate the idea of shooting different shows on one set. Not the most creative idea, but from an economic standpoint, I love it. Reminds me of what our PBS stations does for the city's numerous public access shows. Also kinda reminds me of what Fremantle does for its Youtube game shows. Rearrange accordingly, and you've got four different shows. Smart.
Looking at the Buzzerblog pics, I didn't realize the J! logo is actually on a projection screen. I can't tell; are the arcs on the backdrop part of the projection screen as well, or are they simply moved around the set accordingly?