I just read an interview on GamerEscape and they confirmed that summoner and beast tamer class will be added to the game and that it may even be before 2.0. One of the ideas was to perhaps even make summoner the job for the beast tamer class.

They mentioned that the beast tamer class pets will work the way they did in 11, which is you tame them, fight with them, then send them on your way and the summons will get certain abilities based on your summoners lvl.

As for the chocobos they will have a lvl up as you feed and use it.

Here is the link to the interview. http://ffxiv.gamerescape.com/2011/10/19/gamer-escape-interview-with-naoki-yoshida-the-truth-is-out-there/#more-9022