I was guessing that they were going to do this one day soon. So when I recently bought 2 carry on rollers I bought them from AC, and they are the AC branded ones. (simple black, not like the red ones the FA's have, but they say Air Canada on them).
They are exactly the maximum size allowed and I am hoping that they don't have any problems with their own carry on luggage that they sell and put their name on
.