Alpine changers worked with the addition of a $30 (roughly) adapter... the adapter plugged into the back of the head unit and the changer plugged into the adapter, then the Alpine changer would be controlled by the head units controls. The Alpine changer sounds a tad bit better than the stock changer, and can be purchased for roughly half the price of a Honda changer. The optional changer for the new accord is an 8 disc... the only company that makes an aftermarket 8 disc changer is Panasonic... so it seems as though Honda may have changed things a little.
I'll keep you updated if I recieve any more information.