I'm under the impression that Sunbow also owned the rights for the Conan cartoon, which I'd rather have than GI Joe. Rhino told me they had no plans to ever release it. Hopefully Sony will feel differently.
The DIC episodes don't count. I think the general consensus is that the Sunbow episodes are the "real" series. But Rhino couldn't even finish releasing *them*! It's just the tip of the...*ahem*...Iceberg....