Well we got The Tragicly Hip how about some Bruce McCulloch?
Bruce McCulloch of the Kids in the Hall. A comedy troupe from the 80s and 90s. He did a lot of the musical work. Some of his skits being practicly complete songs. He is affiliated with the Tragically Hip too. One of their songs is in the Kids in the Hall's feature film "Brain Candy" A lot of Bruce's material is comical and just RIGHT for Rock Band. I'm not too sure if i'm allowed to dump Youtube links here so if I can get a response on that i'll link to a few examples.