Hello!
I'm going to start playing Mabinogi open beta in March 5 and found some good nice video in Youtube there you can play your own instrument and music.
This game looking more interesting
Website:Mabinogi.nexon.net
Videos of Music performance:
Mabinogi - Random Playing
Mabinogi - Clannad and Touhou songs
Mabinogi - Haruhi Ending ( Hare Hare Yuka )
Mabinogi - Music Playing (Nanoha)
Mabinogi - Music Playing (Bleach)
Mabinogi - Music Playing (Rozen Maiden)
Mabinogi - Music Playing [Party Performance #1]
Mabinogi - Music Playing [Party Performance #2]