First time I heard of this. -sheepish- I'm not really a big অনুরাগী of Len(my older sister's a অনুরাগী of his but most of the time she listens to an uttate cover instead) so I guess its no wonder.
Title: 朝と夜の物語/Asa to Yoru no 'Roman'(monogatari) Original Artists: Revo of 'Sound Horizon' and a girl from the 'Fiction Junction' project of Kajiura Yuki. Album: 5th Story 'Roman'
This is a nice light song from KAITO, found it recently but only decided to add it here just now.I'm surprised I haven't got wind of this in ইউটিউব until now when it's been there since 2008.
After finding myself in VOCALOID wiki once again, I decided to visit KAITO's page as per usual.Re-reading the "Append - Future of Kaito" as per habit, I saw the link to this.