Madhouse is doing the X-Men up all anime style for a new series debuting in Japan on April 1, 2011 and then coming stateside on G4 later this year.
Madhouse announced a bevy of Marvel projects back in 2009 so it makes sense that the characters look and feel most similar in the anime to the Astonishing X-Men comics. Plus, writer Warren Ellis, who did a run on Astonishing X-Men, has been involved with the project from the beginning. There are already Iron Man and Wolverine anime series out in the wild from Madhouse so X-Men seems like the next logical step.
Not much is known about the storyline at this point, but Animax has posted a teaser trailer for the series and we have it below for your viewing pleasure.