With the "Masterpieces" feature in Brawl outlined in the Dojo update on Friday, many different possibilities in terms of potential upcoming Virtual Console releases have come to light. Because you can't link directly to the site i'll just quote what Sakurai has said in terms of what i am basing my speculation on.
My speculations begin with this comment, "Here you can relive the greatest battles of the biggest star characters through demo versions of their games." This basically states that every playable character in the game, or at least the series that they come from, will have their own "Masterpiece" representation. Considering the diverse cast of charatcers this means there will be a considerable amount of titles to sample from. Games that are not availabale in the Virtual console yet, like a Metal Gear game for instance (as a represenatative of Snake) would be playable, or even game that have never been released in North America, such as a early console Fire Emblem game could be sampled. Why should you be excited about demos of old games? I'll tell you why in this next point.
"If you take a liking to one of the trial versions, you can always buy the full game through the Shop Channel! You might even find a couple titles that divert your attention from Brawl for a while." Sakurai speaks as if each game in the "Masterpieces" will have their own represenatative in the Virtual Console. If Nintendo is to follow Sakurai's claim, before Brawl is released we can expect a flood of classic and imported titles being released before March 9th.
Going even further, the upcoming Virtual console releases may reveal some unannounced playable characters aswell. Albeit this is a little farfetched, it is still a plausible under the previously discussed logic. However, considering the Japanese release is in less than a week, this last specualtion is kind of useless for I imagine everything about the game is going to revealed within minutes of the first purchase. But there is one last VC Monday before Brawl is released, so there is a chance that one of the games may reveal a character (or the series in which they come from at least) before the imminent information explosion. Here's hoping for a Megaman release tomorrow.