Have you looked into the Doctrine Project?
Doctrine2 was inspired by the Java Library Hibernate. It comes with an excellent database abstraction library (DBAL) and a query language called DQL.
They also have some great sidecars like Doctrine Migrations which will look at changes in your data model and generate migration classes for deployment.
Their caching library is used in a load of projects too... their community is all about decoupling code so the components are usable outside of their library.
Doctrine2 is by far one of the most impressive PHP libraries around today.