Here is what I wrote to Samurai Panda:
"Here is what I was able to get from a Google Translation, apparently CoroCoro Comics ( a source for many Pokemon revealings) is going to release a guide on December 15 detailing all the characters in the Brawl. Is this really true, I cannot really understand the rest of the article based off of the horrid Google Translation, so some assistance from your Japanese understanding abilities might be necessary. If this does include all the characters in the game, hopefully, all flame wars on the Brawl character board will be put to rest. Thank you for your time."
Here was his response:
It does indeed say that all characters will be revealed alongside an issue of CoroCoro Comics magazine (in a separate booklet) on December 15, but then the article states that CoroCoro might just be showing all of the starting characters, not the secret characters. This would be very likely given what CoroCoro has pulled in the past in regards to Smash, and it would make sense that we'll have the full starting lineup of characters soon.
So we could find ourselves with the full starting roster soon. If Sakurai plans to release one character each week leading up to the release of this booklet, we are looking at four more characters being added to the starting roster that we do not know about yet, putting it at 25, exlcuding Sonic and Snake who are likely to be hidden.