I haven't done any of this myself, but here are the best strategies I've
read about.
1. get a sound card with enough outs to run your pc into a regular dj
mixer and mix like a regular dj. You would still need some sort of
control surface for transport / effects twiddling.
2. if you want to do scratchy stuff, there's the Ms. Pinky vinyl, and I
think the Stanton Final Scratch works on the same principle. I don't
know, but they might both be vinyl with SMPTE timecode on them.