>
> Do you have anything that is NOT some web application?
>

Bitcoin Authenticator is a desktop app+mobile app pair. It pairs with your
phone over wifi, cloud push, maybe Bluetooth as well. I forget exactly.

It's done in the same way as Lighthouse, so it runs Win/Mac/Linux on
desktop and Android on mobile.

It could be adapted to use BitGo as a third party key holder with SMS
authenticator relatively easily, I think. We did the bulk of all the needed
work last year as part of the bitcoinj multisig work. Then you'd have a
server involved, but not a web app.