I know that you want an American/British native english speaker but you have to consider other kind of people that know about music.
I can write a music with good time (4/4 , 3/4, 2/2, 6/8) , intone (high / low) , scale C , D ,E , F, G , A ,B , # , Bb , frases and everything that a musician can create with imagination, emotion althought I live in Nicaragua.
Consider please my offer. I hope that opportuny, only send what kind of music do you hear.