To whom it may concern,
I believe I'm qualified to undertake your project of completing a vocal score for your piece as well as the backing track to accompany it. I would love to ask more questions about the project itself, but as far as I understand it from your description it fits my skills perfectly. I can finish a vocal score with a rhythm part to accompany it within two days, and (assuming this is what you want) can make up a midi backing track to go along with it in an additional two days time.
I look forward to your response and hope to work with you soon. Sincerely,
Kyle Scherrer