None. There hasn't even been a real world demo where given normal conditions: a running sshd and other programs where a running browser script exfiltrates a key

None. There hasn't even been a real world demo where given normal conditions: a running sshd and other programs where a running browser script exfiltrates a key with meltdown. Spectre probably isn't possible either and that is the easy one. The load store buffer attack seems completely impossible. Even the POC had to essentially write a program specially to be exploited. The attacks are very interesting and neat, but I think things like this and other techniques effectively remove any last chance.