I don't do ethereum audits but isn't the right thing to do here is to write your own wallet contract and have someone audit it? geeezzz people storing 10M$ ethers.. This is the analogous to the case of storing 1 million dollars in a vault with a 1$ lock.
I'd rather use a contract that has been around for a while storing major funds, which has several public, current audits. The Ethereum Foundation has a multisig which has been holding their funds for years, that's probably a good choice. Parity's audit was done before they made a major architectural change.
I do think there's a need for a much simpler standard multisig than the ones being used now.
That requires getting an ed25519 implementation in there with the ability to multisig into contracts. That's what a standard would be if there was to be one.
By "simpler multisig" I just meant a normal multisig contract with less functionality, where the keys still separately call contract functions and update state.
True multisig transactions like you're talking about are supposed to become possible with the next Ethereum upgrade.
