I already use mixxx on a regular basis its a great program

have a look here:

http://www.mixxx.org/

there are already some very beautiful and tactile Midi controllers available (the ddj-s1 for instance) and the lionstracs is a little clumsy looking and looks like it will be fiddly to use with all the small buttons and little data wheels, but having everything in one unit is a good idea if you don't want to take a laptop with you.