I thought to ask whether this would be possible to build.
It is called Mixxx and is according to the applications homepage: "Mixxx is a digital DJ system, where wave, ogg and mp3 files can be mixed on a computer for use in live performances. Filters, crossfader, and speed control are provided. "
I hope that some kind package builder wants to build this as it would be nice to have it for those nice party evenings.
The address for the homepage is http://sourceforge.net/projects/mixxx