PSR-0 Autoloading of modular… anything is now possible.
Put your models in modules/foo/src/Pyro/Module/Foo/Model/Foo.php
Put your libraries or other classes in modules/foo/src/Pyro/Module/Foo/Whatever.php
It might be a bit of an arse adding in that extra folder structure, but this is totally worth it if you're into PSR components. Otherwise ignore it completely and keep using $this->load->model() as you always have, but that will be gone in 3.0.