Realpra - thanks for the link to your thread, lots of interesting information packed in there

I guess more specifically I'm more interested in any standards forming with the protocol of communication between the HW wallet and the client side application like Electrum that has the full user GUI and performs network syncs/comms. I'm less interested in how the protocol is transferred (USB, smartcard, Bluetooth, etc) than the protocol to do things common to HW wallets (sign this, give me a new public key, etc.)
I'm also not as interested in the guts of how the HW wallet secures keys - thats the stuff that will vary quite alot between wallets I assume.
Thoughts?