I've been spiking on this for a while now and today I open sourced the project on GitHub: https://github.com/fgrehm/vagrant-lxc
. It's not a Vagrant 1.1 provider yet but it mimics its actions (up, halt, destroy...) and uses a yaml file for configuration.
Over the week I'm going to create some issues to keep track of what has to be done for an initial release and on the weekend I'll give a shot at turning it on a Vagrant 1.1 provider.
Please keep in mind that this is a result of less than a month worth of LXC knowledge, it is a spike, the code is not clean and requires A LOT of refactoring but at least we have something that works to start with ;-)