What rough balance point do you want for them? You mention ToB so would roughly that power level be what you're after?

Really, though, OA samurai works (less feats than a fighter but more skill points and good Will saves). I'd echo knight (samurai had slightly worse armor and didn't use shields but instead used parrying swords; as for weapons it depends upon period) except that the tanking abilities don't fit.

Really warblade would be the best fit imho with emphasis on Iron Heart, Diamond Mind, and Tiger Claw. They even get Diplomacy