as,
Erm.......have to question your response there! The aircraft cofg must be infront of the aircraft neutral point in pitch for the aircraft to be stable - as we all know! As the cofg is moved rearwards, it approaches the neutral point of the aircraft, and stability is reduced. Thus, the rearward limit of the cofg is a stability limit (as you stated).
During most flight phases, the tail load for a commercial aircraft is a download (look at the tail incidence on a jet after landing!). This would indicate that the effective centre of the pressure of the main wing is behind the centre of gravity, necessitating the tail download to trim. Thus, as the cofg moves forwards, a greater moment is required from the tailplane to trim the a/c. Therefore, the forward cofg limit is imposed as a result of a minimum required control power in critical flight phases i.e. typically at landing, where all high lift devices are deployed and airspeed is low. To extend, the aerodynamic centre of the wing does not HAVE to be infront of the cofg!
Regards,
Cuban_8