In the most recent issue of the Exiles the exiles went to the timebroker's headquarters they showed a monitor clearly showing the Ultimate universe! The exiles have so far visited the 616 universe twice and will soon visit it for a third time during the House of M storyline. Broadly this means that the 616 and Ultimate universes exist in the same multi-verse and are therefore ripe for a cross over. This means it's only a matter of time before the exiles visit the Ultimate universe. Get ready for interdimensional travel between the 616 and Ultimate universe, because it's going to be here before we know it!!!!