CodeIgniter + Doctrine + Smarty?

[eluser]TheActionCombo[/eluser]
I really like CodeIgniter for its simplicity and clear documentation, but its models, caching, and templating are very weak or non-existant.

I was wondering if anyone has had any success using Doctrine and Smarty with CodeIgniter and how well they integrate together.

Also, what would you recommend for Auth? FreakAuth or Zend_Auth?

Thanks.