This is the only thing other than safe storage I am going to ask about without finding out from exploring.

I want a dog. Can you get one? If so, where? (Unless there are big spoilers) Does he level with you?

You can...just do not know from where since i do not have the game just yet and want to find out myself.

All i know is that they cost several hundreds 'o gold and are "bought" from a certain stable?!

I found a dog while out wandering. Named Meeko. He becomes a companion and is unlocked when you stumble across him. He is a big ugly wolfhound looking dog and I saw him on a road and I followed him back to a house where you can interact with him and make him a companion. He is a decent fighter but the companions AI is screwed up. In narrow corridors they just stand and block the way so you cannot move past. While fighting they have a habit of stepping right in front of you when you are attacking something and you wind up killing them. I don`t know haw many saves I loaded because I killed them by accident.

There is also one connected to Clavicus Vile's Quest. Started by a Smith (don't remember which one...). He is actually quite helpful, especially in the beginning, because he is invulnerable...the perfect tank...but he is also extremely annoying...he is not a real companion and conflicts with your sneaking...he 'detects' you, making sneaking virtually impossible...he also has a tendency to stay really close to you, so near that he consistently shoves you around...annoying in most cases, fatal when near a cliff...he occasionally speaks and has some funny lines