Well I still can't find anymore information about the "DRAGON KNIGHTS" album that was supposed to have the Japanese voice acting cast involved. However the "KAMEN RIDER Dragon Knight ED" seems to be coming along.
The album's cover has been released and looks pretty nice. The name of the album itself is "ANOTHER WORLD-Kit x Len", and thus Suzuki Tatsuhisa and Matsuda Satoshi will be lending their voices to the release. The album will be out on June 23.