Those dogs aren't good with smaller dogs like beagles, and cats though are they? They are absolutely beautiful though, and I'd consider one if it would be safe for Gage.
If the dog is going to be Cesar's playmate, I've always heard that you generally don't want the larger dog to weigh more than twice the smaller dog. The local shelter follows this rule for since rough play could get the little dog hurt. So, if Cesar is 25 pounds, they wouldn't let you adopt a dog over 50 pounds.
www.dogbreedinfo.com and www.yourpurebredpuppy.com have good information. The second site gives pros and cons of each breed instead of telling you best case scenario like a lot of sites do.
