Sure, we can prove ownership of some addresses to you. If I message you, I'm not sure it'll turn up in your inbox because I'm a "newbie".
I'm not blocking Newbies from sending a PM.
Do you have a PGP public key?
I tested it a while back, but it was quite labour intensive to work with.
What I'd really love is a mechanism to cryptographically prove ownership of funds and solvency across all Bitcoin addresses, whilst not actually revealing the identity of the addresses.
As far as I know, this isn't possible.