I posted this in the prediction thread.
Usually, Sakurai reveals all the characters by the release of a Smash game
this means, he has until January 22nd to reveal all the characters
....we have 26 confirmed so far (The 23 + Sheik, Ganondorf, and Luigi)
he only has 11 weeks to reveal all the characters
he usually reveals characters once every two weeks
that leaves us with about 5-7 characters left.....leaving us with about 29-31 characters...which is rather pathetic
29 characters is the amount you can get if you take the icon sizes shown in the demo, and multiply them throughout the screen.
If the sides of the screen DO fill up, we have 7 characters left. If they don't, well, we only have 1 character left. However, assuming Sheik, Ganondorf, and Luigi are confirmed, chances are, the sides of the screen with the "?"s are going to fill up. Leaving us with 4 characters left. My assumptions are that they are Megaman, Krystal, Game & Watch, and someone from the Metroid series.
Widescreen TVs
Fullscreen TVs
You may be thinking that the icons could shrink to make room. That is a possibility. But keep in mind that never happened with Melee.
I can see about 25 stage spots there. We have 16 confirmed now. That seems like a reasonable amount for about 30 characters.
PS: I made these mockups.