Zardnaar
Legend
Monsters would take a lot of work. You'd want to rescale CR to level to get the 1v1 model of 4E encounter design, but this already lines up with CR a bit with the new encounter calculator.
Monsters would probably fairly easy, changing the CR might be the easiest and staple on some 4E mechanics. I've used 4E monsters in 3.X and SWSE, AC and abilities changing is the main thing.