I thought I had seen someone had built some Common Cartridge support for course import, but I can’t find it now. Am I imagining it?
We had a hackathon at edX last week, and a few of us tackled a Common Cartridge converter. The result is messy, but works, at least on basic courses.
The code is here: https://github.com/openedx/cc2olx
It needs work. If you try it, let us know what you find. If you want to help build it out, we want your help! Get in touch.
It is great to know that Open edX is working on this feature and will have full functionality in future, I’ll keep following this thread @nedbat and would be very happy to see any update.
Thank you. 
Thanks @nedbat for sharing your work here.
I find it useful as it converts course outline very well and also converts some of the problems.