Just come across these on Spotify, literally dozens upon dozens of albums. All lullaby versions of songs by bands like The Cure, The Smiths, The White Stripes, Blur, even Silverchair. I'm slightly obsessed with their rendition of Nirvana's On A Plain which is here http://open.spotify.com/track/0FOOVsy1buLDcNb2tIf0ZK
The link to their main page on Spotify is http://open.spotify.com/artist/5bHjVR4F2Tfq4Ha6x7K6wU