http://houndsaroundtown.com/style/summer-dog-boots.html
http://www.northsailsgear.com/store/?c=33
Personally, never used either of the two as my dogs would bite my hand off if I did...One thing to keep in mind that for dogs - especially larger breeds - that they require the ability to spread there 'toes' and claws to obtain balance...it would take fairly substantial amount of time to get them accustomed to them as well and could effect their swimming ability...
best thing to do is just keep them trimmed and or walk them constantly on concrete surfaces to wear them down and allow their pads to 'get roughed up a bit'...
Only a opinion (a worthless one most likely at best) ...not my thing (not my dogs thing either but then they weight 90 lbs a piece and are the boss of me not the other way around...)...
Let us know how it fairs out for you if you go the route and the 'experience' would be interesting
