I am currently in the market for one right now too. I have been to a few locations so far and here is what I have found:
1) Sobie's BBQ at 162 Willowdale
They have a great selection. Mostly highend stuff. One brand they sell is an infra-red burner (TEC, I think is the name); quality of burner you would want in order to match the searing quality technique of places like Mortons, etc. Very nice but Not cheap. Units run $2,600 + tax.
2) Appliance Canada at 8701 Jane Street and Ontario Gas & BBQ at 3310 Langstaff Ave (just around the corner from AC). They have the full range of Broil King, Weber (same as Sobies) plus others such a Dacor (kitchen appliance mfger), etc. The thing about the Webers, that I do not like, is their penchant for placing all the controll knobes on the table surface, robbing you of working surface. Go figure.
Have to agree with Perry Mason about the B&W's. Not sure if having a side burner is necessary but then, if Toronto ever got another black-out, boy would that come in handy to boil water on the side while you cook your meals.
Anyways, my hunt continues this weekend. My limit is $500. I'll check out the Cosco and Dickson Pro. There are a number of Home Hardwares that sell them too; Guzzlevet, how about you checking out the Sams and we'll compare notes later (whats your cost limit?).