Docker 0.11 is the Release Candidate for 1.0
blog.docker.io
blog.docker.io
There is now an execution driver API (which was indeed planned for 1.0), and now it's a matter of the community contributing and maintaining a BSD jails driver that works :) There are several efforts underway, but we (the core developers) can't contribute and maintain every driver possible, it would be too much work.
If you're interested in participating come say hi on #docker-dev on Freenode, we can help you get started :)