Capcom's Ultimate Marvel vs Capcom page said recently that the Vita version of the game would be ditching a paper manual in favor of an in-game digital manual. It appears that this may be a common exclusion for Vita games.
Inside Games managed to get a Vita game just ahead of tomorrow's release. They shared pics of the inside.
The package consists of just the game card and a single sheet of paper showing warning messages and details on a firmware update that's included on the card. There's no actual paper manual inside.
Inside says that PlayStation Vita games do away with paper manuals in favor of digital manuals that can be accessible from the game. It's unclear if they actually got official notice of this from someone, or if they're speculating based off this single game. We'll have to wait until all the launch titles can be examined tomorrow.
Inside also showed a size comparison of the Vita game card and other memory devices, including an SD card, a Micro SD card and a 3DS card.