Unfortunately, that is correct -> someone else has done cascadian airways. You could maybe send this user (http://www.airline-e...er/80462-pasti/) a private message asking about using his livery, or having someone else make a different livery for your version of Cascadian?
As for Talon, what colours do you have in mind, and what is your current fleet? (no point putting the livery on a 737-300 if you operate 737-800s!)
Do you want a modern livery or a retro livery, or a 1994' style livery, since I see that R7 is at 1994?