Definitely looks like some sort of arranger as I've just paused the video (the 2nd link is better) and you can see speakers at either side of it, quite a few buttons, a small display, only 61 keys and 1 mod/pitchbend wheel.
Could be a Gem or possibly Korg?

One site on Google mentions that the singer has even used a battery operated Casio before with just him singing (brave soul) so maybe this is a newer electronic Casio

[This message has been edited by Craig_UK (edited 06-24-2006).]