Via Joystiq, a picture of a rumored/possible game controller for the next Nintendo console: Lots of people thinks it's a fake. It may be. Anyway, I found it interesting to report this design here since it makes me think of a paper by Leganchuk, Shumin and Buxton: Manual and Cognitive Benefits of Two-Handed Input: An Experimental Study (ransactions on Computer-Human Interaction, 1998). In this article, the authors explore the potential benefits of such two-handed input through an empirical research:

bimanual manipulation may bring two types of advantages to human-computer interaction: manual and cognitive. Manual benefits come from increased time-motion efficiency, due to the twice as many degrees of freedom simultaneously available to the user. Cognitive benefits arise as a result of reducing the load of mentally composing and visualizing the task at an unnaturally low level which is imposed by traditional unimanual techniques. (...) Overall, the bimanual techniques resulted in significantly faster performance than the status quo one-handed technique, and these benefits increased with the difficulty of mentally visualizing the task, supporting our bimanual cognitive advantage hypothesis. There was no significant difference between the two bimanual techniques. This study makes two types of contributions to the literature. First, practically we studied yet another class of transaction where significant benefits can be realized by applying bimanual techniques. Furthermore, we have done so using easily available commercial hardware in the context to our understanding of why bimanual interaction techniques have an advantage over unimanual techniques

This paper is a must read for people interested in two-handed computer input, it provides a relevant literature review (not up-to-date but pertinent anyway).