I'm jumping in with both feet here and posting a small piece I wrote as part of a piano collection called Intervallic Etudes. This is the first etude called: Nasty Feelings and is based on the interval of the 7th. Be forewarned, it is not a 'romantic' composition. I used Finale 2006 with GPO and the Ambience set to a Recital Hall.
For a 'pretty' sound see my Impending Doom.