Here are the latest Vocaloid 3 Developments and demo songs! Not much information has been given to them all, however all of them include a demo of some type.
Bruno and Clara
Spanish Vocaloids have been announced by Voctro Labs and a demo song has been released (above). Check out Voctro Labs’ Youtube channel for other demo songs. Bruno and Clara are currently slated for a December 2011 release.
Cul
Originally a mascot for Vocalo Revolution and voiced by VY1, Yamaha announced that Internet Co. Ltd. would be creating a new voicebank based off the voice of Kitamura Eri. Not much information has been leaked about this Vocaloid, however a demo song was played during the Vonama Live, and you can listen to it here.
Tone Rion
Tone Rion is a new Vocaloid being developed by MoeJapan with art by Akio Watanabe. She will be born (?) on December XX 2095 and is 16 years old. Her official website is here and a demo is below.