This is going in a different direction, I have myself and I LOVE it, I have two trurntables and DVS set up at the same time due it's clever routing. You will need at least an Audio 4DJ (two channel scratch), but best with an Audio8DJ, then you can get all 4 channels running independently.
http://www.behringer.com/news/behrin...12-tech-award/
http://www.behringer.com/EN/Products/DDM4000.aspx
loading tracks is done with DVS, I use the mixers effects (not traktor), and the best bit if the computer crashes, it's a real mixer ...just put on some real vinyl.