Crypton has just announced on their Twitter account a sample of a new Append for Kagamine Rin called Sweet. You can hear this new demo by continuing to read below.
This is also mention of an Append for Len called Serious, so perhaps we will hear a sample very soon. This may just be a rename of a previous Append. We will be sure to update you on any more news.
Info source: Vocaloid2 CV Twitter updates – here and here
Additional reference: Piapro blog