[thwarted]

I've been experimenting with something similar over the past couple of weeks, at the HTTP auth level (as that's my use case), although I don't have browser integration yet as I'm still working on interfacing to ssh-agent (also, insert standard lack-of-time excuse here).

I've been experimenting with SSL client certs for a while. They don't have a decent UX/UI in any browser I've used (redxaxder provides a link in another thread) and are a significant hurdle to general adoption. We could maybe see significant process in this area if some well known, popular site, like Facebook or gmail, supported SSL client certificate authentication.

We need to see more work in this area.