Just sent the first few thousand packets over an IPv6-only
PPPoE uplink provided by rh-tec.
Config on OpenBSD with bge0 as the physical interface
connected to the DSL modem:
ifconfig pppoe0 pppoedev bge0 authproto pap peerproto pap \
authname 'thename' authkey 'secret' up
After a few seconds, pppoe0 receives a Router Advertisement and
gets it's prefix. The rest is plain sailing (ssh -6 and so on).