Great proposal @larry, efforts working towards better interoperability are important.
I am concerned about the non-standard derivation path usage this would entail, though. These bitcoin addresses belong to the m/44'/5757' chain.
Hardware wallets—at least Ledger—lock down their apps to only sign on the respective SLIP-0044 defined paths. This proposal would either need to accept that limitation, or find ways around it. Whether that’s lobbying hw wallet manufacturers to make exceptions, or publishing new apps that handle multi-chain concerns etc