Something like this with musicians from around the world made for "Playing For Change" done last year could work. Missed this when it was made.. excellent version.
The Weight | Featuring Robbie Robertson and Ringo Starr| Playing For Change | Song Around The World
Benefit concert for whom? The monies would be squandered like it always is. How about local benefit shows where the money is picked up by the clinic, hospital, or agency after the show? Sorry, I am very skeptical about these mega shows; they usually end up just making people 'feel good' but achieve very little.
Ronnie and Ben Waters doing a 'telethon' would be more beneficial. Hell, have the Stones do a live telethon.