Why subject yourself to all of this unnecessary "trolling" if you can simply prove that the funds are still there and in control of all or any of the aforementioned escrows?
I'm not sure what's more funny, the fact that people think they're entitled to make such a request or that they think that there is a standard for signing messages from multisig. Actually, it's rather sad how ignorant and/or envious you (not directed @you) have to be to do so. 
There was absolutely no proof provided for any of these claims, thus there is absolutely no public proof necessary to counter any of these claims. This is QS shenanigans all over again. Some people never seem to learn.