No, Canada never used harriers (would have been nice though).
I'll agree with Tango 1 that its a great "what if" project. The best selection of Canadian aftermarket decals I know of is from Arrow Graphics. They have a lot of generic Canadian markings from all eras of Canadian military aviation that include national insignias, Canadian style numbers and stencilings as well as the various squadron markings.
Good luck. post a picture if you decide to do the "what if" with it.