Monster Cable and Beats Electronics have filed a lawsuit against Fanny Wang Headphones, sister company to Hard Candy Cases and Gumdrop Cases, alleging that Fanny Wang’s recently debuted products infringe on a design patent and trade dress for the Beats by Dr. Dre headphones, and engage in unfair competition. The suit claims Fanny Wang’s headphones are deliberate “knock-offs” of the Monster/Beats Studio and Solo model headphones,…