I asked Sennhesier USA this question:
Here was their response:I have heard that Sennheiser plans to release a new Headphone, sometime this year or next, the HD700. What information can you share with me about this new product?
Is this conclusive on the subject or not?Hello -
Thank you for your inquiry and interest in Sennheiser. Although Sennheiser is always working on developing new products and exciting technologies, there is no plans for a future flagship headphone at this time. The so-called HD700, although quite legendary in the rumour mill, does not exist. The HD650 will continue to be the flagship headphone for Sennheiser.
If you need additional assistance, please do not hesitate to contact me.
Eric Palonen
Headphone Specialist
Sennheiser Electronic Corporation