A 4e product for sale right now. Saying "For Use with Fourth Edition Dungeons and Dragons" right on the cover...
Not using the GSL.
This was a predictable outcome of the GSL. However, I doubt we'll be seeing a lot of this sort of stuff. Mr. Raggi ponders whether this example makes the who simulacra thing redundant. Possibly, but only if you've got a copyright lawyer handy and you're fairly certain Hasbro won't sue you. Keep in mind that Hasbro doesn't have to win the lawsuit. They just have to inflict enough financial hurt that you decide never to be crosswise with them again.
But Kenzer can probably get away with it, and we may see a few other companies poke their toes in this water as well. But I don't expect to see many, forget most, 4e material released in this manner. And I don't expect we'll see any simulacra follow this example.