Both XMod2 (
http://www.cat5camp.com/xmod2/) and JAPlus Mod (
http://japlus.fragism.com/index2.php) have special features for duelers. 
 xMod2.6: 
 Can set the amount of force required\drained for special saber moves and katas
 Automatic "anti-laming" (turning off saber and standing still for x seconds makes you immune from sabers and Force).
 Can set whether or not sabers ignite automatically when the duel starts
 Can set the starting health and shields for duelers
 Can set ending health and shields for duel winner
 Can set time a player must wait after they finish a duel before starting another
 Can set the number of multiple simultaneous duels allowed
 Has several types of duel ending messages
 Can keep duelers from seeing chat while dueling to reduce distractions
 Makes rolling like Jedi Knight II: Jedi Outcast (can chain rolls, can backroll without hopping first)
 Can have JK2-style flipkicks
 Can make single-saber Yellow and Red DFA like JK2
 Can reduce saber throw damage to ~30
 Single-player-style pull-stab available  
 JAPlus 1.8 
 Multiple duels at once
 Flipkicks 
 All SP attacks added + Total new attacks and new DFA
 Configurable saber Damages
 fixed roll
 improve single saber yellow DFA 
 can change saber type without respawn
 can force players to make an automatic BOW move at duel start