All right, let me try.
Courage the Cowardly Dog was cancelled on the 102-episode (4-season) contract. I am tempted to say the same for Camp Lazlo and My Gym Partner's a Monkey, but they might have been cancelled due to lack of interest.
Sheep in the Big City was cancelled probably because Mo Willems moved to work on Codename: Kids Next Door or to write his books (not too sure on this one).
I am unsure about Time Squad, though the last episode may have something to do with it.
Whatever Happened to...Robot Jones? was cancelled because the creator was upset with the amount of executive meddling in his show.
Was Generator Rex cancelled over toy sales, too?
The Problem Solverz and Secret Mountain Fort Awesome, as well as CN Real, were likely cancelled over negative reception. I am tempted to put other shows in this category but cannot be sure enough to justify them (Mike, Lu & Og and Squirrel Boy come to mind for me).
Courage the Cowarldy Dog, Camp Lazlo and Generator Rex weren't cancelled but simply ended their run.
Sheep in the Big City was cancelled and most of its crew went to KND. It was obviously cancelled due to low ratings, despite having the hightest-rated premiere of all Cartoon Cartoons.
If Sheep weren't cancelled, KND would have looked quite different.
