I saw an R-pod with a similar tent attached in Tampa. I don't know if they're sold separately, as that R-pod had a different model number, ending with a "T" for tent.
In reference to the R-Pod tent, My husband, Adrian and myself rented an R-Pod in May 2009 and the tent was included. Setting up was tricky although I guess if you did it enough, you would get it down pat. the size was good but they had a long track to slide the side in and I think a 13' scamp
because of the curve it may not work, the R-pod is taller too, and maybe height may be an issue. The pods I think were made by forest something. If I remember correctly the salesman said the tent was a 600.00 cost.
I have been looking for a screen room and I just might go back and look at those again