Sorry for bumping an old thread, but I'm amazed at the potential for this type of cloning technique.
This actually looks very possible. I've done some research on hops (ie Humulus lupulus) which is in the Cannabaceae family, and root cloning is the most popular way to propagate them. Though hops have a much stronger root than cannabis (hop plants will regrow from their roots from the previous year) I believe that cannabis would be able to do the same thing. Hops contain a rhizome which is an underground stem.
I'm a new grower but I believe using a root from the 3rd order lateral part of the root system of cannabis would be about the same as a rhizome.
link:
Hop Rhizomes: What, how, and when
Perhaps a stem could even be turned into a kind of rhizome by planting it with rooting gel or putting it in a bubbler. This would be ideal for shipping clones over long distances or storing genetics for long periods of time. I will soon be harvesting my own crop and will try saving some 3rd order roots and also creating a rhizome-like stem. I'm planning on moving soon so this will get a real test.
I'll make a post with links to any useful research I find on this, what methods I used to prepare my roots, and hopefully good results. I didn't have a lot of time for this post but I wanted to get my thoughts out there to see what the community thinks of this.