Sorry, I meant DIR-615/825 not 655/855. You are correct, the 655 does not support IPv6 at the moment. According to Dlink support forums in 2009 there were plans for the 655 to get upgraded but I haven't heard anything since.
Note: the way Dlink has done the IPv6 upgrades on the other models is by releasing a new hardware revision. So DIR-615 Rev C,D, and E supports IPv6, but Rev A and B don't. =\
