Securing hardware wallets

I would like to solicit feedback on a whitepaper I wrote about securing hardware wallets even if the hardware or software is compromised. Let's consider turning this into a BIP.

Abstract: With wide adoption hardware wallets present a very tempting target. Once enough wealth is controlled by a specific hardware wallet model, attacking the supply chain of the wallet becomes attractive. Malware could be inserted in hardware or software. The random seed could be generated in a way that is predictable to the attacker or the seed could be leaked.

The paper describes a way for a "Warden" computer to manage a hardware wallet in a way that protects the resulting private keys from compromise.

https://github.com/devrandom/btc-papers/blob/master/hardware-wallet-security.md