In Salt Lake, the only shop I know of is Wasatch Mountain Touring. They sell boats but I get the impression whenever I'm in there that none of the guys are really paddlers. SLC isn't known as a boating mecca. Skiing, mountain biking, hiking, funny underwear? Yes. But boating? No. This can work to your advantage. I scored a good end-of-season deal on a ZG54 at this store. If you find a boat or paddle you like, make a cash offer of $50 to $100 less than their asking price. It worked for me. They're located on 7th East and 1st or 2nd south - can't remember exactly. Give them a call at 801 359-9361 and they'll tell you how to get there.
In Ogden, there used to be a cool paddle shop on Riverdale Road. Not sure of the name, phone number or address but if you look in the yellow pages, you should find them.
I think Park City has a paddle shop but their inventory may be all stuffed away in the back rooms because of the upcoming ski season. Even if there aren't any paddle shops Park City is a cool place to hang out and drink a few.