Extreme Boat Sports is a great dealer here in the lower mainland and they carry both Supreme and Centurion as well as they get a lot of used boats in. They actually got their start in bringing boats up from the US and reselling. Your other dealers are:
http://www.nautiques.ca/cs/ - MB
http://www.performancewatersports.com/ - Malibu
http://tige.ca/ -Tige
It all depends on what your budget is. I would also wait over the winter and wait until closer to spring when the CL adds will start to pop up more. I just bought a newer boat last spring here and I still look on CL weekly to see what's around and what boats are worth. Be careful though. Although some people paid a lot of money for a boat up here I still don't believe an 07 XStar (or similar) could be well over $ 50k. I've seen one still for just under $ 80K which is stupid.