Docker works fine with rackspace, doesn't it?
edit, pricing: As Performance Cloud Servers roll out, they will replace Standard Cloud Servers as our default offering.
I'm assuming what he meant is support for deploying Docker containers directly rather than renting a server and installing Docker on it and running your containers in that.
I am actually working on a service where you can easily deploy VPSs that have Docker installed on them with a control panel for conveniently managing the containers. I can then have features like a menu option to move containers between VMs and automatically creating DNS and proxy configuration for container-based virtual hosting. I.e. you click a button on the container and just type in the sub domain or domain name next to the public port exposed by Docker and then that gets automatically set up so you can access that service on that container through a domain name.
I wonder how long until Rack space and the rest provide a Docker container service.