I just discovered "Sleep" by Max Richter, an 8 hour and 24 minute album described by the artist as "an eight-hour lullaby...a piece that is meant to be listened to at night." I have trouble mixing sleep with anything but the sound of a fan, but this sounds like excellent music to work to. I plan to give it a shot this week.

You can listen to the album on Amazon and Spotify (amongst other places).