Preventing /node/<nid> access

I don't think I can easily create a patch, but here's the code I added (with some context before and after). You'll want to replace contenttype with the machine readable name of the content type you want to enable this for. This is where you can see what a hack it is. Ideally there would be a configuration page with a list of your content types to enable this for.

At a basic level the first if looks for urls of the node/ format and makes sure there is no query string (edit, delete, etc). I then look up the node id in the db and check it's type. I then redirect the user to the homepage with a 404. It would be better to send them to the official 404 page, but so far I haven't found the correct method to do this.

    // Get the request string (minus trailing slash e.g. node/123/)
    $request = preg_replace('/\/$/', '', $_REQUEST['q']);

    if (preg_match('/^node\/([0-9]+)$/',$request,$matches)==1 && $query_string == "")
    {
        $node = node_load($matches[1], NULL, TRUE);
	  if ($node->type == "contenttype")
	  {
	        drupal_goto("/","",NULL,404);
	  }

    }
    
    // Check the path (eg, node/123) for an alias. If one is found, redirect.