If you haven't looked at it lately, take another gander at the Phantasy Star 0 website:
http://phantasystar.sega.jp/pszero
They've added a lot more information lately. Of course it's all in Japanese and Flash based, so some of us can't read it. There are some videos up, however. You can see gameplay and some anime cutscenes. There's also a release date of Christmas this year, but I suppose that's only for Japan.
Unfortunately, one of the videos they have up looks to put the final nail in the coffin of the classic series.

It shows past games, but starts with PS Online. Apparently Sega now thinks of "Phantasy Star" as being online the online games.