In the Ultimate Magic, the bard's Masterpiece "Dance of 23 Steps work almost like Combat expertise.
Spoiler:
The Dance of 23 Steps (Dance)
This complex dance makes you difficult to strike.
Prerequisite: Perform (dance) 4 ranks.
Cost: Feat or 2nd-level bard spell known.
Effect: The shuff ling steps, bends, and leaps of this intricate dance make you a difficult target to hit, but also make it more difficult for you to perform other actions.
When using this masterpiece, you take a –2 penalty on melee attack rolls and combat maneuver checks, and you must make a concentration check to cast any spell (DC 15 + the spell’s level), but you gain a +2 dodge bonus to your Armor Class. When you have 8 ranks in Perform (dance), and every 4 ranks thereafter, the penalty increases by –1 and the dodge bonus increases by +1. You can combine this masterpiece with fighting defensively and Combat Expertise, but not total defense. When you use this masterpiece, it lasts until the start of your next turn. Abilities that extend the duration of a bardic performance (such as Lingering Performance; see page 164 of the Advanced Player’s Guide) affect this
masterpiece; this allows you to get multiple rounds of its benefit (and its penalties) at the cost of only 1 round of bardic performance.
Use: 1 bardic performance round.
Action: 1 free action.
The problem is that with this masterpiece, it's a free action to activate so, as written, a bard can make all his attacks without penalty and then activate the masterpiece to gain a dodge bonus to his CA during the rest of the round. The only draw back would be the penalty to hit with his attack of opportunity.
