From this BBS:
歌姫ベスト くま太 2006/Oct/17 Tue 12:38
Earlier, the elusive W(本物)さん posted a comment on the same BBS revealing that the 歌姫ベストdue to be released in November has been cancelled and possibly postponed till January. Later today, the above comment (supposedly from Universal) was posted to explain the cancellation of the album.
Apparently, according to my interpretation (I think Hamu ちゃん and 乱火ちゃん can help here）, it looks like they are making changes to the setlist and they have decided not to postpone but cancel it. Hamu ちゃん wonders if it is copyright issues on her blog but I wonder if it is the copyright for the new songs that they want to add which is causing a problem.
It is likely to be released in January at this point and although it is disappointing, they say that we will have something pleasing to look forward to. Is it going to have many more new songs? Is it going to be another "Empress" (as in the expectation that there will be new material and then disappointment) because it was delayed as well? Is it budgeting issues because I thought it was going to be released under her own 歌姫 label? Maybe she just realised that 2007 is going to be her real 25th anniversary instead and decided to make it then?
It’s a real shame because she can’t ride on the wave of promotion together with the movie. Anyway, I think the timing could be better because everyone is trying to release albums at the end of the year, so maybe she might earn more if she pushes it till next year when people have less to choose from and more to spend.