Module to embed content in a iframe?
In your node--contenttype.tpl.php you can add a div (optionally with a textbox) which is hidden by default and fill it dynamically with the title and content of your node. Create a button that uses the colorbox module to show that div when pressed and your done. 

&lt;div&gt;
  &lt;textarea&gt;
    &lt;iframe&gt;
      &lt;h2&gt;&lt;?php echo $node-&gt;title;?&gt;&lt;/h2&gt;
      etc..
    &lt;/iframe&gt;
  &lt;/textarea&gt;
&lt;/div&gt;


Alternatively you could just use javascript to copy the content of your page to a div when the button is pressed.