<?xml version="1.0" encoding="utf-8"?>
<FxApplication xmlns="http://ns.adobe.com/mxml/2009">
	<Script>
		<![CDATA[
			import com.candycoatedsyntax.control.Controller;
			import com.candycoatedsyntax.business.Services;
			import com.candycoatedsyntax.model.ModelLocator;
			
			private var model:ModelLocator = ModelLocator.getInstance();
			private var services:Services = new Services();
			private var control:Controller = new Controller();
		]]>
	</Script>
</FxApplication>

Cairngorm pretty much just works in Gumbo straight out of the box.  Only hiccup I found was that you can't instantiate the services and controller components using mxml tags.  Just define them once in the main application using ActionScript and you should be good.

Cairngorm in Gumbo

Flex

MXML