Check out
Cabela's Official Website - Quality Hunting, Fishing, Camping and Outdoor Gear at competitive prices. they are a hunting gear supplier and most hunting suppliers also carry a large assortment of "water dog" equipment for retreivers. Doggie float coats with handles, etc. designed for a working dog not just designed pretty for the pet store.
Boat shoes for a dog? Not really, most dogs hate booties. If you keep his nails trimmed and any fur between the pads trimmed, he probably will get enough grip on the decks. When and if that doesn't work--you can try the boots but I've met a dog that didn't want to tear 'em off and chew 'em up, other than some trained rescue dogs that have to work in rubble all day.