The barrier to password-less logins is not technology. It's user adoption.
You can create all the protocols and tech stacks that implement public-key crypto, but getting everyone to use it over passwords is the problem - not the technology.
A browser-based solution has the most chance at being adopted, so you should focus your efforts on supporting Mozilla Persona and other browser-based logins. We'll start to get there as soon as people realize the solution has to be browser-based.
You can create all the protocols and tech stacks that implement public-key crypto, but getting everyone to use it over passwords is the problem - not the technology.
A browser-based solution has the most chance at being adopted, so you should focus your efforts on supporting Mozilla Persona and other browser-based logins. We'll start to get there as soon as people realize the solution has to be browser-based.