If this rumor is true, we'll be getting even more 'nuclear GPU' jokes.
This is madness, almost on a level we haven't seen before, though that wouldn't be entirely accurate. Now, before I let myself write anything more, I do want to warn you: This is a rumor, from a sometimes questionable site, who in turn claims to have gotten the information from a non-disclosed source. That said, we do hope that there is some truth to this.
Here it goes: According to the Chinese section of VR-Zone, a reliable source has told them that AMD is planning to make a dual-Hawaii XT graphics card. Now, for those of you who don't know, the Hawaii XT GPU is the same one that is used in AMD's current flagship Radeon R9-290X. If this is true, we might be looking at a card with up to 5632 stream processors, 128 ROPs, and 8 GB of GDDR5 memory (4 per GPU), along with a dual 512-bit memory interface, which will be marketed as a 1024-bit memory interface.
While it remains uncertain what the real name will be, it is rumored that the AIBs are going with Vesuvius, named after the only active volcano in Europe. The model number is rumored to be 'Radeon R9-290X2,' though this could be interpreted as either a dual-290X, or a dual 290.
Unfortunately, that is where the rumor ends. Little more is known so far, and we have no idea when more information will surface, if at all.