Replace Code Igniter's database layer with Doctrine 2

[eluser]WanWizard[/eluser]
Have you even looked into this before asking?

As far as I can see, Doctrine doesn't use CI's database layer at all. It imports CI's database config, and uses PDO to directly connect to the databases...

And you don't want to replace it, believe me. Doctrine is dead-slow compared to CI's database layer, it's a bit pointless trying to convert for example sessions to use Doctrine.