hmmmm. Stumped on this one. I don’t think that anyone has in earnest done that. My best friend from high school and I used to sing a lot together, I guess in effect she has sung to me. And the song that jumps to mind is Rush, Tom Sawyer. She loved them more than I did, but they are still pretty excellent.
oh, actually I could also choose Endless Love, I used to sing that as a duet at Karaoke…so I’ll include as a bonus.
theresa-omalley.com 
I’d love to hear what you think :)