Are there any children's shows that have been rebooted as adult shows in order to grow with their audience? I'd totally watch the Fairly Odd Parents with adult humor.
Samurai Jack's final season comes to mind. The first couple of episodes were amazing. It took the best parts of the show and made it a lot more serious.
They didn't reboot them as shows, but Invader Zim and Rocko's Modern Life got some modern 90 minute features and they were very much made for the adults who grew up with the old shows.
To a lesser extent, the same with the Animaniacs reboot.
Closest I can think of, despite it probably being more of a show aimed at teens and young adults, would be Ren and Stimpy with their failed Adult Party Cartoon. Other than that, I can't think of any examples.