I've been researching the very well-regarded configuration management framework 'salt' and I wanted to report that it has Gentoo support:
Portage Config Module: http://docs.saltstack.com/ref/modules/all/salt.modules.portage_config.html Portage Config State: http://docs.saltstack.com/ref/states/all/salt.states.portage_config.html ebuild module: http://docs.saltstack.com/ref/modules/all/salt.modules.ebuild.html - Grant