You can pick up the kit for about 290. Koolance makes it.
Xbox 360 LCS kit
Though you can build a much better kit yourself and for less by going with their supplied interior setup, but buying a different pump/rad/res.
And then buying a decent 350-400LPH pump, a small acrylic res, and a single 1x120 or 140 rad. Put a fan on it and call it a day. Don't forget tubing/fittings/liquid.