I think this would be extremely valuable to obtain given the current conversation about aoe caps. It's really hard to talk intelligently about the subject when we don't even have a list of what the caps are, obtained via reliable sources and methods.
Testing this in pve is a real pain. We should setup a neutral location in Cyrodiil to meet and get these numbers. Maybe one of the organized pvp guilds such as Votf could volunteer to be the testers? And the rest of us could just show up to be the test subjects?
I doubt we are going to get a complete list from Zenimax, and there has been some questions as to how candid they have been with us on this subject. I'm not saying they haven't been, but we need to test this for ourselves.