No, mainly because it would be business suicide for whoever is involved. Especially if neither party is willing to pay for transit to the other... IPv6 is still small enough that it doesn't yet force one providers hand over the other.
That being said, if you are single homed on HE only then I would suggest you purchase transit elsewhere as well, or find a datacenter that has multiple transit providers. Being single home is dangerous.
The real question is going to be how long can Cogent hold-out. HE is willing to provide them free IPv6 peering, why not accept it so that their customers can get a full IPv6 table...
Peering disputes are problematic for both IPv4 and IPv6. This has nothing at all to do with the IP version!
(p.s. You do realise that the article you linked to is from 2009 ...)