Using simplemachine forum functions in a codeigniter controller

Question

I'd like to use codeigniter to write an interface to an existing simplemachines forum. I'm aware of the SSI api, but that provides limited functions like showing 10 most recent posts.

I'd like access to all the native SMF functions so I can show all my boards, and all the posts in the boards.

Are there one or more files I can include into my codeigniter controller to gain access to SMF functions like getBoardTree() (in Subs-Boards.php).

Has anyone ever accomplished this type of integration?

For example:

//in controller
$data['boards'] = getBoardTree();
$this->load->view('my_view');

//then in view
<ul>
<?php foreach($boards as $board):?>
    <li><?php echo board['name'];?></li>
<?php endforeach;?>
</ul>