News! There's an error in an official Smash Brothers Brawl video on the Japanese Wii website that pretty much confirms Lucario from Pokemon as a playable character, possibly replacing Mewtwo. Oh, and Ness is there too.
Here is the explanation, quoted from someone else. I've tried this myself and it does work:
"Now, first off, above all, I know people are making some ridiculous claims all the time about who they think should be or is going to be in Brawl~ But this time, I present to you some pretty strange material that could allude to Ness and Lucario being playable characters in Brawl. Bear with me, read on, and you'll see what I mean.
The second-last Brawl update on the official site (from the date I posted this journal) was one detailing Sticker-powerups usable in the Subspace Emissary single/dual-player story mode. (
http://www.smashbros.com/en_us/gamemode/modea/modea12.html) Basically, the point is that you can place stickers you find in-game on a character's trophy-base to add powerups to their abilities. (For the Subspace Emissary only.) They don't mention it, but the icons in the bottom-right show what characters they can be used on. (
http://img144.imageshack.us/img144/5491/brawlstickersiconsmn1.png) Also, note that some of the stickers had their icons cleverly removed. (
http://img132.imageshack.us/img132/9910/brawlstickersnoiconsjt5.png) This either means that the sticker works for everyone, or that the icons were doctored out to protect their super-secret characters from being revealed.
Now, on to part II of our story:
There's a Japanese site, showing a game play montage of Super Smash Brothers Brawl (That many of you may not have seen -- check it out as it's imperative to my point:
http://wii.com/jp/movies/smashbros-movie1/) It shows a bunch of fighting, basic gameplay strategies -- but the real kicker is at 4:20 - 4:22, where it shows a stickerbook that highlights Groudon, Lucas, and Sonic before flipping pages. The stickers, unlike the screenshots on the update-page above, do not appear to show any character icons -- it merely passes them by and goes on to the next scene.
Now, this may seem like a stretch, and I hope this works the way it worked for me -- bear with me, and please just try it, I know someone else was able to work it correctly as I learned about this possible hint from someone on Lulz.net.
The moment it flicks to the sticker page at 4:20 and shows Groudon highlighted, pause it immediately -- again, you can't see any icons. But now, unpause it, and watch very carefully, very quickly -- something happens in the following second, the video vertically reformats, and for a second you can see text and icons appear -- here's a screenshot in case you can't view the video, or aren't fast enough, or just don't feel like trying it:
http://img86.imageshack.us/img86/7606/lucariozoomll7.png. First we have Pikachu, the PokÈmon Trainer, and.... what's that third one?! Is it Lucario? -- Oh yeah, and there's Jigglypuff there, too.
As well, try the same thing a short moment after, pause the movie when Groudon is still highlighted, only a moment before it shifts to Lucas -- you'll see this hidden screenshot emerge when it vertically reformats:
http://img98.imageshack.us/img98/5512/nesszoomls8.png -- You can see Ness' icon there, beside Lucas'. (I think we all honestly expected Ness to return, but this might make things seem a bit more concrete. On such a note, just my opinion, but I expect the majority of (if not all of) the cast of SSBM to be back. At least the biggest main ones that everyone's whining abut, like Ganondorf and Captain Falcon.)"