Loading libaries, helpers, configs, models etc at call-time

[eluser]micha8l[/eluser]
I was thinking, by way of overloading, is it possible/recommendable to load a model or something at call-time.

Standard codeigniter way:

Code:

$this->load->model(array('blog_model', 'blog_posts_model'));
$this->blog_model->do_something();

Without loading beforehand

Code:

@$this->blog_model->do_something(); // ??

I'm just trying to refactor my code by cutting down on maintenance and lines used. Please tell me if this is possible/been done/bad idea, etc, etc?