Capcom V.P. Christian Svensson was on the Unity Boards today talking about how long it takes for a port of a game to make it online as a downloadable title. Here's his comment.
Just wondering on average how long does it take to port a game to the Playstation Network and XBox Live? — Jay
Sven: We haven't done a lot of "ports." We've done some enhanced versions of existing games, that because of those enhancements have taken a good deal longer than just a straight port would (adding online to anything, as an example, is a major feature add).
Our average XBLA/PSN project length is about 14 months from greenlight to live on a given service. Our low end is probably about 12 months.
This is interesting because if/when Marvel vs. Capcom 2 becomes a reality, it's assumed to have online play. If this ends up being the case, that means that project has been in the works for some time and has been kept 'mostly' quiet during this period.