Zend_Db_Table and Zend_Db_Table_Row are fairly good at what you're describing. You don't need any configuration file, most metadata is "discovered" from the database itself.
Technically these classes don't implement the ActiveRecord pattern. Instead, they implement the Table Data Gateway and Row Data Gateway patterns. Together, these offer similar value as ActiveRecord, and in some ways are more flexible than ActiveRecord.
But as with any ORM, there are inevitably some SQL queries and operations that you can't do through the OO interface. No ORM can serve as one-stop shopping.
Footnote: I worked on the Zend Framework project for a little over a year, especially on the Zend_Db component. But I don't work for them anymore.