The recent Lemur 4 update added many new features to the legendary control surface app. DJ Traxus has taken advantage of one of those features to program the first platter controller for Lemur that will actually behave like a record platter. Previously you could use a knob to advance or rewind, but now you can actually hold the track position, the same way you would on a real turntable.
The Traxus Scratch Live template is available for $10 on DJ Traxus' site. Here is a demo of it with Serato.