I have a pair of Sennheiser 540 reference (300 Ohms) to sell. I believe they were the top of the line of Sennheiser about 10 years ago. They are in excellent condition (check the appended photos) and they sound superb.
I realise that I practically don't use them, since I also have the HD 600s.
I would sell them for $150 + shipping. You can e-mail me directly at "firstname.lastname@example.org".
I live in France. The shipping would be around 7-8 $ for Europe, around 10 $ for North America, around 15 $ for Australia (exact costs provided by request, I have to go to the post office to get them).