Although this is in no way confirmed, it has been rumoured before.Apparently, after the success of The Matrix the Wachowski brothers were offered the next Batman film – Year One. Not only that, but they were offered full creative control for the film, as well as the option to work on a Batman trilogy. However, the Wachowsi Brothers, despite being bit Batman fans decided to simply focus on the Matrix series.
One point from the article, is that apparently the Wachowski Brothers, and Joel Silver have been given $600 million for the remainder of the Matrix series, this includes Reloaded and Revolutions, the AniMatrix projects and the recently announced online Matrix game, which is apparently costing $45 million to make.