I had considered this as a potential workaround. X-callback urls open the linked document in the editor only though.
To be honest, my intention was to use the preview window as a sort of personal wiki of all my local Editorial documents, like I currently do with Trunk Notes. I'm trying to migrate over to Editorial though and it's a hassle having to sift through a directory tree with hundreds of similarly named documents to find the one I'm looking for.
If I could create an index document with links to local files and short discriptions of each file it would make my life so much easier. It would be pretty amazing also if I could serve up individual directories and browse to them with Safari or another machine on my local network. It would be nice if Pythonista and Editorial had a separate, shared directory. I doubt apple would allow such a thing.
In any case, thanks for the reply! I may ultimately end up having to go the x-callback route.