Kluge....I think you will find it impossible in this era of political correctiveness and equal rights to find an airline that would refuse to sell a Business Class (or First for that matter) seat to children. If a family wish to spend that money on their little ones then no airline would risk declining their business, not only because we are currently in a recession but also because they would be terrified of the discrimination suit that could be filed by the family!
Just remember, screaming kids were around long before airplanes and business class travel!