[briansmith]

Which CA's will issue short-lived certificates without negotiating a custom ($$$) contract with them?

[agwa]

Google Trust Services lets you go down to 1 day using ACME. No payment required.

[kmeisthax]

Let's Encrypt, they said a while back they want to allow issuing certs for fewer than 90 days.

[schoen]

That's true, although it's still not possible to actually get one yet.