Pretty much.

A Docker AMI Generator exists. DigitalOcean offers an out of box Docker host. OpenShift will replace cartidges with Docker. OpenStack can provision Docker containers. Other PaaS/IaaS are in the works.

Running a registry is as simple as `docker run samalba/docker-registry`.

Pushing to that registry is very simple, especially if you have a reverse proxy ( I use hipache. Mine is registry.stinemat.es )

So, assuming those first 3 are in use in a 'convenient' way (as defined by you) - your request exists today. That matter of convenience will grow.