It is not that common for non-reference cards to follow the launch so closely but we heard that at least some non-reference GTX 590s will be announced, if not even launched in the first weeks after the official launch.
We still can't confirm any details on how high will the actual factory overclock be and what kind of cooling would these non-reference cards go for, but it is nice to know that they're on the way. Some partners might even go for the full custom design with its own PCB. The GTX 590 is the new Nvidia's flagship and we are quite sure that some partners will try to squeeze a few MHz from the card, despite its high TDP.
The information is pretty scarce at the moment but we are sure that we'll know more after the official launch tomorrow. Of course, if Nvidia indeed gave the green light on custom designs, partners will definitely do their best to stand out of the crowd.