Personally, I'm expecting TGS. Gamescomm would be nice, but TGS seems more realistic. December for PSX is a bit too far off, but even if it doesn't make that show, I'll be pretty bummed, but never turn into one of the vitriol trolls calling it vaporware.
The original Dreamcast games were projects from at least 1996 onward (at least a rough guesstimate for the Dreamcast work, not Saturn version), which weren't revealed until late '98. Even after, Suzuki didn't show much of it, really. At least not compared to today. He's old school, let him play it close to the chest. We all know he will make a great game one way or another.