Sadly, nothing new on this front. I'm also waiting for a music editor since I'd like to add some music actually played in the NBA during timeouts and such.
I've been bothering the good people in this forum with my consistent asking about a music editor about once a month
Jaosming told me that the music editor for 2K9 came about at a pretty late stage, but I'm hoping the 2K10 editor will come a bit earlier.