I think this would be really good idea, but I'm not sure how easy it would be to do. AFAIK its very hard to get an entertainmant licence for an event like this. I know of another sound sytem that did a similar thing a year or two ago (tents, soundsystems, projector screne cinema etc) with land owners permission but without the correct licences and although the police didn't shut it down they did come down quite hard on the land owner after the event in terms of quite a hefty fine.

Definatly something worth looking into and certainly something i would be interested in if you can find a way to do it.