I am a music teacher who teaches photography on the side and am just getting started into head-fi. You are right, this hobby is quite painful on the wallet. To help me get started I am trying for an unusual trade. I have a used Canon EOS 70-210 3.5/4.5 USM lens in very good condition (optics are perfect) and want to trade it for a pair of HD600/650. I bought this lens for $430 a few years ago.
Please pm if you have any questions. I can e-mail pictures if you are interested.