SEGA has in a recent itw with famitsu 360 stated that they were willing to develop SHENMUE III but needed the support of an exclusive platform in order to sustain the costs and the eventual insufficient sales.
Personnally i would be so glad to be able to play a now-gen (or next gen) SHENMUE 3 i would actually buy it twice, that's right, twice.
All that we need now is a platform with the balls and the cash to sustain the project.
http://scrawlfx.com/2010/01/sega-interested-in-shenmue-iii-worried-about-sales