Yeah, I believe Obito's dead and gone. I doubt Kishimoto would bring him back to life, because as you said, recycling characters is illogical and silly.
If you're keeping up with the manga (I'm not that up-to-date myself, but I've read far enough to ascertain some facts), and assuming that my memory's not faulty, it's revealed that Tobi is in fact Uchiha Madara. He discards the Tobi persona after Deidara's death. I'm still a bit puzzled as to how he's managed to remain alive all this time, but according to Itachi before his death, Madara is immortal.
Is there anyone else keeping up with the manga? I haven't been on AO in months so I'll have to reacquaint myself with this place again.

