http://www.ps3center.net/news/4293/sega-talks-shenmue/
As I mentioned in my previous post, Famitsu 360 just put out it's annual Japanese developer interview issue. For the developer issue, Famitsu polls developers to see what their upcoming plans for the Xbox 360 are, which by extension, usually ends up pertaining to PS3 owners as well.
In this year's issue, Sega talked a bit about the oft-requested Shenmue follow up. It's a title they still think a lot about doing, however, sales are a factor. Neither of the previous games sold well, so Sega is hesitant about returning to the franchise. They reassure fans, though, that if there is an opportunity to revisit the franchise, they would love to do it.
Sounds like Sega is hoping that one of the platform holders fund it, perhaps in return for an exclusivity deal.