Doubt it for now, the HD 5970 is still the undisputed king of graphics cards atm. I'm thinking it will stay that way for a long time, because GTX 480s won't be able to be bought until April, and mass distribution won't begin until past June. Then, it will take a few more months for nVidia to develop a dual GF100 card, because a single GTX 480 uses more energy than a dual-gpu single card HD 5970, and to get two GF100 GPUs on the same card, nVidia's going to seriously have to either rework these cards or cripple them severely to be able to put two on the same graphics board and not exceed the 300W ATX limit on graphic cards.
As for branding, the GPU underneath the graphic card's heatsink is still the same, two HD 5870s underclocked to 725MHz/1000MHz. However the ability to overclock them is limited by their coolers - most are reference design, but soon enough there should be non-reference like Sapphire's Toxic/Atomic or Vapor-X editions, or HIS's IceQ. Although right now AFAIK there are no non-reference design coolers.