The admin recently put out a call for player ideas, submit your! Mixing a caster class with a melee class is the prefered method I believe (taken from the Paladin Splash Poll pg 3).
Paladin/Druid would have synergies with WIS. Paladin/Bard would have synergies with CHA. Paladin Wizard would be wierd and force choices over STR/INT/CHA or STR/INT/WIS Paladin Sorc would be yet another quasi that uses Sorc but have synergies with CHA Paladin Cleric would have synergies with WIS but doesn't look that appealing does it?
How about the ultra wierd Paladin/Palemaster... DeathKnight... oooh ahhh