Alas! I've figured something out! I'm hoping my website won't explode after I've done these things:

1. I copied /concrete/controllers/profiles to controllers/profile and /concrete/single_pages/profile to single_pages/profile.

2. I created files.php, to add to controllers/profile, with some basic cut-and-pasted code from controllers/profile/edit.php:


<?php
defined('C5_EXECUTE') or die("Access Denied.");
Loader::model('user_attribute_text');
Loader::model('attribute/categories/collection');
class ProfileFilesController extends Controller {

var $helpers = array('html', 'form', 'date');

public function __construct() {
$html = Loader::helper('html');
parent::__construct();
$u = new User();
if (!$u->isRegistered()) {
$this->set('intro_msg', t('You must sign in order to access this page!'));
Loader::controller('/login');
$this->render('/login');
}
$this->set('ui', UserInfo::getByID($u->getUserID()));
$this->set('av', Loader::helper('concrete/avatar'));
}

public function on_start() {
$this->addHeaderItem(Loader::helper('html')->css('ccm.profile.css'));
}
}

?>

3. I created a second files.php, to add to single_pages/profile, consisting of some basic cut-and-pasted code from single_pages/profile/edit.php:

<?php defined('C5_EXECUTE') or die("Access Denied."); ?>
<div id="ccm-profile-wrapper">
<?php Loader::element('profile/sidebar', array('profile'=> $ui)); ?>
<div id="ccm-profile-body">
<h2>Filed</h2>
</div>

<div class="ccm-spacer"></div>

</div>

4. I added "Files" as a single page at the dashboard (Pages and Themes).

5. I checked it, mysite.com/profile/files, and the header ("<h2>Files</h2>") shows up!

That means it's working, right?

But I'm still not sure how to correctly merge edit.php and avatar.php. I'm thinking about condensing each set of these files in controllers/profile and single_pages/profile. Will that work?

No response yet? I'd like to know as well.