Love, love, love this idea. Here's how I would like to see it implemented:
At level 90 in Animal Lore, OR, at level 0 in Dog Training, you can tame a Wolf into a Pet Dog that will follow you around.
Add a skill called "Dog Training." Using that skill, you can pet your dog (lvl 0), train it simple commands and tricks like Sit, Stay, Go Home, Fetch (for light objects) (lvl 30). At higher levels, you can train to to be a Hunting Dog (lvl 60), a Guard Dog (lvl 90), or an Attack Dog (lvl 100).
To regulate overuse of Attack Dogs, here are some ideas:
1. Limit number of dogs in general, or Attack Dogs in particular, to 1 per player. (I personally don't like this idea. I think since there are no NPCs, we should be allowed to have unlimited dogs.)
2. To train an Attack Dog, you have to be lvl 100 in Dog Training.
3. You cannot command a dog that another person has trained...
4. And/or, you cannot command a dog unless you are the same level required to train it.
5. You can't convert any trained dog to another trained dog (i.e. you can't train a Hunting Dog to be an Attack dog).
6. Dogs are high-maintenance; they eat a LOT of meat.
Other features that I would like:
-The dog reverts back to a wolf if you forget to feed it. Good idea, Stewbailey!
-You can name your dog. +1, wupang!
-If you are lost, and you have trained your dog Go Home, it will lead you home.
I am a dog lover and have trained several. FWIW.