クラス継承順を整理して考えるより、js上でクラス継承キューを作った方が早いです。

用例

$class('ThumbQueueView',$extends('View',{
	draw:function(){
		$('Body').innerHTML = '<div id="ThumbQueueAsExternal"></div>';
		this.drawSWF({
			name	:'img/swf/ThumbQueue.swf?'+time(),
			id	:'ThumbQueueAsExternal',
			width	:'100%',
			height	:'100%',
			vars	:{}
		});
	}
}));

//↓継承する View クラスが後に来てても通る

$class('View',{
	draw:function(){},
	drawSWF:function(swf){
		swfobject.embedSWF(
			swf.name, swf.id, swf.width,swf.height,
			'9.0.0', 'img/swf/expressInstall.swf',swf.vars,
			{allowFullScreen:'true',allowScriptAccess:'always'},
			{id:swf.id,align:'middle'}
		);
	}
}

var view = new ThumbQueueView();
view.draw();

ソース

//要 prototype.js

var $classes	= {};
var $classQueue	= {};

function forEach(obj,func){
	if(Object.isArray(obj)) {
		for(var i=0;i<obj.length;i++) {
			if (obj[i]) {
				func(i, obj[i])
			}
		}
	}else {
		for(var key in obj){
			func(key,obj[key])
		}
	}
}

function $class(name,obj){
	if(Object.isArray(obj)){
		if(!(obj[0] in $classQueue)) $classQueue[obj[0]] = [];
		$classQueue[obj[0]].push({
			className:name,
			superClassName:obj[0],
			contents:obj[1]
		});
	}else{
		var c = ('isSubclassOf' in obj)?obj:$extends(null,obj);
		c.className		= name;
		$classes[name]	= c;
		window[name]	= c;
		
		if (name in $classQueue) {
			forEach($classQueue[name], function(i, value){
				if (value.className) {
					$class(value.className, $extends(value.superClassName, value.contents))
				}
			});
			delete ($classQueue[name]);
		}
	}
}

function $extends(parentClass,classMethods){
	
	var superClassEnable = true;
	if(Object.isString(parentClass)){
		if(parentClass in window){
			var superClass = window[parentClass];
		}else{
			superClassEnable = false;
		}
	}else{
		superClass = parentClass
	}
	
	if(superClassEnable){
		var c = Class.create();
		if(superClass) Object.extend(c.prototype, superClass.prototype);
		Object.extend(c.prototype, classMethods);
		c.superClass = superClass;
		c.isSubclassOf = function(object){
			if(!this.superClass)	return false;
			if(this.superClass == object)	return true;
			return this.superClass.isSubclassOf(object)
		}
		c.prototype.self = c;
		return c;
	}else{
		return $A(arguments);
	}
}