You say you want an object representation, which I would interpret to mean that nodes become objects, and the attributes and children of the node are represented as attributes of the object (possibly according to some Schema). This is what XMLObject does, I believe.
There are some packages that I know of. 4Suite includes some tools to do this, and I believe Amara specifically implements this (built on top of 4Suite). You can also use lxml.objectify, which was inspired by Amara and gnosis.xml.objectify.
Of course a third option is, given a concrete representation of the XML (using ElementTree or lxml) you can build your own custom model around that. lxml.html is an example of that, extending the base interface of lxml with some HTML-specific functionality.