Just browsing YouTube as you do... saw this vid:
https://www.youtube.com/watch?v=DDdjHHvb8YM
Looked like a bit of a dicky setup, but wait until you see the edge at the end...
Yeah not bad!!!
I have been trying to find a quicker way to do BIG edging jobs, was almost going to go out and buy at Atom edger then I saw this vid - even better IMO. Only thing is, it's a bit of a home invention - I don't think there is anything like this available for retain purchase??