libvirt-python version 1.2.9 (latest version on pypi) is missing methods when compiled against libvirt 1.2.10 from brew.
After opening a connections, the only methods the connection object implements are close, virConnGetLastError and virConnResetLastError.
Apparently the API XML format has been changed in version 1.2.10 (/usr/local/Cellar/libvirt/1.2.10/share/libvirt/api/libvirt-api.xml when installed from brew) Simply install the old 1.2.9 version:
brew edit libvirt
change url and sha1
url "http://libvirt.org/sources/libvirt-1.2.9.tar.gz" sha256 "95931a5a52f451b9ab73d6a5ae11a5740e1ba69a66520c2a0cffc6068a7e8fc4"
uninstall libvirt and reinstall from source
brew uninstall libvirt brew install --build-from-source libvirt