I know Satoshi is claimed to possess 1.1 million BTC (which would be an insane amount)
But who are the other really large holders and how much do they own? Roger Ver? Gavin Andresen?
I remember someone claiming that Ver owns about 300.000 BTC, is there any place where this is confirmed?
I have checked
http://www.bitcoinrichlist.com but they only show adresses and we cant know with certainty which of those are connected.
Are there any confirmed large holders, who openly talk about the amount they possess?
No ome will tell if they are one of the richest in bitcoin industry. Because all of us thinks that we are the poorest. However, in regards to the information that you provided that Satoshi has 1.1 Mil BTC, then he will be the richest man in the whole world!