So, found out you can get the 668b from http://www.greenflymusicsupply.com/store/Avlex-HD668B-Enhanced-Bass-Headphones-p3882.html .
It's advertised as the "avlex" but that is just the company that owns the superlux line as far as I can tell. For what ever reason they don't show in google searches from this website, while the 681's do. but they have them!
At 39 bucks, seems pretty good compared to paying ~80 dollars for international shipping prices + euro conversion rate.
Edited by Duncandun - 6/10/10 at 11:14pm