Other guests people might be interested in are Ryo Horikawa (Vegeta) and Akihiko Yamashita (animation director for Howl's Moving Castle).
I had been hoping, since I had a dream the night we beat XenosagaII, that they would get Soichiro Hoshi. They have ten GoH's now, and three voice actors, so maybe that dream wasn't as prophetic as I'd hoped, but there's still time before the convention. Also, just because they're not a GoH, doesn't mean they won't be there, a fact proven to us by Tomoko Kawakami back in 2001.