No cross over yet.
All the main characters are known (Mystique, Psylocke, Angel, Sabretooth, Magneto, M, PhantomX)... Only one I don't know all that well (because he came in at the time I had given up on understanding or caring about UXM is PhantomX, who to me, is just Stormshadow from GI Joe... he's the only weak link in the book).