Single-slot fans (excuse the pun), your prayers are answered. Galaxy is working on a single-slot, air-cooled GeForce GTX 680. With a name that translates to "GeForce GTX 680 Warriors' Edition", Galaxy's card takes advantage of the fact that since very compact GK104 PCBs can be made, and the TDP of the chip is a manageable 195W, the equation can be turned around to make a long single-slot graphics card.
In the picture below is this new looking cooler. With no specifics to go with, it's hard to guess just how long the cooler is. The cooler follows the same design principle at work in coolers of GeForce 8800 GT and Radeon HD 4850, that of a compact lateral-flow fan guiding air through a dense network of copper channels, where heat is dissipated to the air. These copper channels draw heat from a copper plate (probably vapor-chamber, in Galaxy's case), which makes contact with all hot components on the PCB, including the GPU, memory chips, and VRM. Hot air is guided out, from the top of the card. There is no further information about this card at this time.
Source: Alex Lam Expreview