I assume that you're talking about obtaining a root SSL cert private key.
In order to do this using this exploit, you'd need physical access to a machine that has that private key stored on it already (presumably a few very high security servers at Verisign, etc).
I'm pretty sure that you'd find it easier to compromise such a server remotely using some other attack not discussed here. I'm also sure that companies holding such a key take their security very seriously.
In short, I don't think that this side-channel attack is even close to being applied to anything but a DRM system; certainly not to a root SSL cert.