Bards should be able to play multiple instruments as their bard level increases.
Once a bard reaches level 4 (and has multiple instruments on their person) and uses perform they will have a unique toggle able ability on the right side of the action bar. This ability will (when activated) allow the bard to magically play a second instrument at the same time. This second instrument will trigger a performance check on NPCs who failed the first performance check. See below for bard level requirements for playing multiple instruments.
Lvl 1 - 3 bard: Play a single instrument at a time.
Lvl 4 - 6 bard: Plays a second instrument at the same time.
Lvl 7 - 9 bard: Can play three instruments at once.
Lvl 10 - 12 bard: Able to play up to four instruments at the same time.
The effect that can trigger should be similar in look to when you cast "song of rest" or perhaps "duplicate self" with multiple copies of the MC playing different instruments near by.
These abilities will have no other impact on the game aside from listed above.
