Just found AKG M220 Pro headphones on Massdrop for $49.95. They are described as an entry level unit. With the exception of the pluggable cable entry on the left earcup; they look suspiciously like the Superlux 681's
There is also a redesigned HD 650, as a Massdrop special for $199.95. Ship date is listed as Dec. 18, 2017. Good price, looong delivery date.