Re: 7X03 A Town Called Mercy (Grading/Discussion) (SPOILERS!)
When Liz Sladen died, BBC was smart enough to simply end "The Sarah Jane Adventures" rather than trying to recast Sarah or to retool a Sarah-less version of the show. But since then, I've heard that BBC has regretted not having a nice strictly kid-oriented Who spin-off in the CBBC line-up. And I seriously think (hope) they're maybe getting ready to fill that empty niche with Amy and the Last Centurion.
That might work. During their last story, the Doctor learns that Sarah Jane has died. Since Amy and Rory never had a chance to raise their daughter, they end up adopting Sarah Jane's "son."
"Live long and prosper."
-Abraham Lincoln to the train conductor at Gettysburg, PA Novemember 1863