I just checked at amazon, and season 3 is #709 in dvd sales, is that somewhat good? Mabye good enough to get season 4 in reasonable time?

I think we'll see Season 4 in March. At least, I hope we do. I noticed they were sold out at Target when I went last Sunday. This is one of Sony's best-selling TV dvds, I think.

Season 3 didn't do as well as the first set becasue there was a lot more competition when Season 3 was released. I agree that we'll probably be seeing Season 4 this Spring.