As we know, most musical instruments makers are from there (Yamaha, Roland, Korg).
About Roland factories (that were hit in 1995), they are now located mainly 100-200 km south-west from Tokyo (Shizuoka, Hamamatsu, Matsumoto).
We can however expect the RD-300NX, due to this month, to be delayed.
UPDATE : Roland, through a statement at its site, expressed its support for victims, and indeed confirmed that its factories and offices weren’t damaged (and there is no casualties among its employees), and that they are continuing normal operations. They are however investigating impact on their business.
Steve Jobs also made a statement (Apple still had setted up a donations program at iTune Store) to its Apple Store employees there (that served as communication points for many people)