Chaos is really a cool character, we agree there.
Have you ever played Xenogears?
It's a similar game made by the same gentleman that created Xenosaga.
It was supposed to be 5 games, but he ran into the problem of the PS2 coming out before he got the green light to finish the saga on the PS1.
Poor guy doesn't seem to have had much luck with completing his game-series on either platform.
It's too bad because both were very good IMHO.
I'm hoping we get a Xenosaga type game trilogy for the PS3 or Xbox 360 before the next generation of consoles comes out.
That whole style of pseudo-metaphysical sci-fi world is very attractive to me.