According to a recent IGN with Chris Hines (Commercial Director of FreeStyle Games) the developer is planning to release at least three more mixes in late November that feature newcomer David Guetta, and Hines notes that FreeStyle intends to bring more new artists to the DJ Hero track list. Hines turns cagey when the topic of new characters or turntable/guitar mixes comes up, stating only that it's something the developer is "looking into" for future DLC.
When asked about the added expense of DJ Hero DLC when compared to Guitar Hero or Rock Band tracks, Hines cites the cost of licensing multiple songs per track and hiring a professional DJ to mix the content as justification for the increased cost. Those willing to shell out for the new content should keep an eye out for the Guetta Mix Pack scheduled to release on November 24th, which features mashups of "Sexy Bitch," "On The Dance Floor" and "Love Takes Over" for $7.99. Due to technical limitations, on the same day all DJ Hero DLC tracks will become available for individual purchase on the Wii version's in-game store for $3.00 apiece.