D-Link DIR-615, not 100% confirmed yet, but after reviewing a user's screen shots of the device's web interface out of the box, it appears to let you configure a 6in4 tunnel on it, and plug in the routed /64 to hand out to your LAN.
I'm going to run out to a store and see if I can get one. Mostly for personal use at home, aside from testing it for this HCL. I'll post some screen shots if I can get one and confirm.
I'll have screen shots that hopefully I can sort into example configurations.
EDIT - Looks like this model needs to be HARDWARE Rev. C
EDIT 2 - ftp://ftp.dlink.com/Gateway/dir615_revC/Manual/dir615_revC_manual_300.pdf
start at their page 48, does native, pppoe, 6to4, 6in4