Me being a dummy, just to verify I understand this right
$node->extras['module_something'] = array('#type' => 'form_box, '#value' => $module->something, '#default_value' => 'lorem ipsum ferrets and mounties and bubbles and things');
<?php form_render($extras['module_something'); ?>
The key to this is the #type - if I want to provide some custom, non-form types, can I use #vlados_secret_passion ?
By default render function uses either the order specified, or the #weight property you add.
The only requirement is that you need to only have 1 parameter for the theme function (an associative array). You can re-use any theme function you want by just adding a small wrapper function, like such :
function theme_form_box($form) { return theme_box($form['#title'], $form['#value'] . $form ['#children']); } theme_vlados_secret_passion($form) - not nessesarily theming a form element, just a theme function