Well, one on one deathmatch in JK/MOTS isn't much fun unless you are both really good.
However, you can play Coop together on those special coop levels (like Theft on Nar Shaddaa and ChaosFor2, find them at massassi.net (
http://massassi.net) ).
Otherwise, probably the only thing that I would consider fun in JK/MOTS with only two people would be a saber duel or five. ; )
Kurgan