UPDATE: It seems Capcom wasn't too careful about where they hid the remaining "Ultimate Marvel vs. Capcom 3" characters, as members of NeoGAF spotted artwork for each of the 12 new characters on Capcom's servers. If you're not worried about spoilers, the full list is at the bottom of this post.
Original Story: If you thought Capcom was limiting its re-releases to the "Street Fighter" franchise, you clearly don't know Capcom. As the publisher that basically inventing DLC in cartridge form back in the 90s, the company has seen plenty of success with recent re-releases like "Super Street Fighter II Turbo HD Remix" and "Super Street Fighter IV Arcade Edition," even if it hasn't seen much success in keeping its game titles under 6 words. It recently expanded the trend outside of "Street Fighter" with the upcoming "Dead Rising 2: Off the Record" and now they're giving the re-release treatment to "MvC 3" with "Ultimate Marvel vs. Capcom 3," coming in November for $39.99.
Like its other re-releases, "Ultimate Marvel vs. Capcom 3" adds a handful of new features, including 12 new characters, which brings the roster to 48 characters in total. Capcom has revealed four of those characters, with Strider (of "Strider") and Firebrand (that annoying flying demon from "Ghosts 'n Goblins") joining Ghost Rider and Hawkeye on the Marvel side. Eight new stages will also be added, likely pulling from both the Marvel and Capcom universes for inspiration.
For more hardcore fans of the series, a Spectator mode has been tossed into the mix, which will allow folks to watch competitions as they happen.
Unfortunately there doesn't seem to be any mention of a downloadable option for those who already own "Marvel vs. Capcom 3." Granted the game does come in at $20 less than a normal console release, but Capcom has already shown that they're able to add new characters and modes with a DLC update in "Super Street Fighter 4 Arcade Edition," so it's a bit of a shame that's not the case here. Of course, for diehard "MvC3" fans, that really won't matter.
FULL ROSTER
Capcom
Strider
Firebrand
Vergil
Frank West
Phoenix Wright
Nemesis
Marvel
Ghost Rider
Dr Strange
Nova
Rocket Raccoon
Hawkeye
Iron Fist
A gallery of all the characters in Capcom's signiture "MVC3" art style can be found on Joystiq.