Since I've covered all the other instances of “custom” Radeon HD 7990 Malta graphics cards, I may as well write about the dual-GPU model from XFX.
Like the ones from AMD's other partners, the XFX AMD Radeon HD 7990 has two 28nm Tahiti GPUs, 6 GB of GDDR5 VRAM, a massive dual-slot heatsink with three fans, the Whisper-quiet Fan Technology, and, of course, the eight games shipped as part of the Never Settle Reloaded program.
Sleeping Dogs, Far Cry 3 Blood Dragon, Far Cry 3, DEUS EX Human Revolution, BioShock Infinite, Tomb Raider, Crysis 3, and HITMAN: Absolution make up the august list.
Like for all other newcomers, the XFX HD 7990 costs $1,000 / €1,000. Check with local retailers to see if it's available, or look it up online. The product page is here