This is an idea we could chew on for days. Is this even possible, given who we're talking about? And if possible is it at all desirable?
I agree that having them all in Dublin at once and feeling like they have work to do is very uplifting. I may have some candy floss and ice cream to celebrate.
Anything's possible.
Though given the more artistic leanings of Bono/Edge vs the more conservative leanings of Larry/Adam, how would they do it ? I think if they felt like it, they'd do it by now. I think they like having someone else overseeing producing and having that extra input.
Zooropa did have Edge co-credited but that was just a one-time happening as he was chewing into the record, what with his marriage falling apart. I think Eno and Flood had a bigger role...