Expected to be unveiled at CES, the GTX 295 (nee GTX260 GX2) actually is made up of two print-circuit boards, and each one has a GTX 200 GPU, 240 stream processors, 448-bit memory bus and 896MB DDR3 memory. It's totally outrageous, in other words, and requires 289W of power, so I hope you've got a behemoth of a power supply.
The price, while unknown, will be proportionately juggernaut-sized, crushing your wallet. Since it's designed to beat ATI's Radeon HD 4870 X2, it'll likely fall in the same price range, probably around or slightly north of $500. It could swing cheaper though, since Nvidia's current high-end card, the GTX 280, is trending south of $400 at the moment. Guess we'll see, but I can't afford it either way.