I have created a small file template for creating custom Event classes quickly and easily using IntelliJ IDEA. Simply go to Preferences > [IDE Settings] File Templates > Create a new template [click the + icon] > Name it i.e. ActionScript Event | Give it an extension i.e. as | enter the below script and your sorted. Now if you right click on your project and select New > ActionScript Event you can enter the couple of defined params and your done and dusted.

package ${PACKAGE_NAME}#if (${PACKAGE_NAME} != "") #end{

import flash.events.Event;

public class ${NAME} extends Event {

    public static const ${CONST}:String = '${CONST}';
    #if (${eventObject} != "")
    public var ${eventObject}:${eventObjectClass};#end

    public function ${NAME}( type:String,
                             #if (${eventObject} != "")
                             ${eventObject}:${eventObjectClass},#end
                             bubbles:Boolean = false,
                             cancelable:Boolean = false ) {
        super( type, bubbles, cancelable );
        #if (${eventObject} != "") this.${eventObject} = ${eventObject};#end
    } 

    override public function clone():Event{
			return new ${NAME}( type,#if (${eventObject} != "") ${eventObject},#end bubbles, cancelable );
		}
}
}