I think that is a great idea and sounds really fun. I would definately go to one if I was invited. I have a tendency to not only spoil my dogs but other's dogs as well.
I wish I knew alot of dog people, I could have really used a puppy shower. Unfortunately most of my friends and relatives are not big dog people and even if they do like dogs that arn't into spoiling them like I do and they think I am crazy for treating my dogs like children. I really don't see any difference in a baby shower and a puppy shower. To us our puppies are our children.