Crypton Future Media has released Meiko, a new Vocaloid library based on Japanese female singer Meiko Haigo's voice, which is steady, straightforward, and suitable for any musical genre.
Their web site is in Japanese so I won't attempt to summarize the product here, suffice to say the list price is ¥19,950 YEN and some audio demo songs are available.
English readers can read an english translation of the page, courtesy of Babel Fish.