Hello,
I am very much interested to do this work by c# as i have strong knowledge in it and most importantly i have developed many windows service program using it and interact with FTP. I saw your provided doc file and i understand all and i can assure you that i can develop it efficiently. Only i have objection on your requirement point #7. As it would be a windows service program, it is stoppable by users, but if you make the service auto, it will be start again once the computer is restarted. Let me know if this okay.
Thanks