For Google and my forgetful self:

To merge two contacts in Kopete into one, right click on the contact you wish to be added to the other, go to the protocol menu (usually last) and choose *Change Meta Contact*. Now search and pick the one you want to add it to.

I’ve had to redo my contact list a few times, and I’d been doing it to most braindead of ways: Removing contacts and readding them under the right meta-contact… Still this isn’t the most obvious of workflows.