Last time CanJet was shopped around, WestJet wasn't interested - and that was before WestJet started up in earnest out east. I'm going to guess that the appeal for WS to acquire CanJet is even less, now.... equipment, personnel and route structure compatability isn't there.
It will never happen, there would be 2 bases and a small senority issue if WS were to merge (yuck) the two. WS wants nothing to do with senority issues, and multiple bases.