I actually did this a while ago. I wanted to try out creating a docker base image from scratch so created one for RHEL 4 and then launched it as a container on RHEL 7. I didn't do too much with it other then prove out that I could run processes in it, but as far as I could tell it was functional. And the weird looks I got from people when I told them about it were great!

Disclaimer: I work for Red Hat.