I think if we were to get a guest next year, it should be a mangaka. This is because VAs have kinda been done before and there are lots of interesting mangaka out there. It would also be much more interesting to hold a panel with someone who creates the content of anime and manga rather than simply performs it.
Hrmmm... drawcard mangaka would be, like, the creators of the big-name Shonen series like Bleach, Naruto, One Piece... Akamatsu (Love Hina, Negima) is also a possibility, as is Azumanga/Yotsuba creator Kiyohiko Azuma... I can think of a few I would personally love to bring over, but whether or not they would be major attractions is elsewhere (Koji Kumeta [Sayonara Zetsubou Sensei] and Kio Shimoku [Genshiken])
The problem with getting a manga-ka is....... their schedule and $$
Manga-ka's run on a very darn tight schedule and they would expect us to pay for their fees (mangakas are poor too, big name mangakas are darn busya nd ten times more expensive, not to mention SMASH is at a precarious time when alot of work is being thrown at them.....)
Even if we try to get CG artists....... it will be more or less the same but easier to get, unless we have relations, it is hard...... go ask around, and see if there are any ppl who know any.