AFAICT, Linode doesn't offer that, and they probably won't. Amazon's been ahead in this arena for awhile, and will probably keep that lead for the forseeable future. EDIT: Apparently they do have an API which would cover a decent variety of use cases.
What's sad is the number of people that migrate over to Amazon because it's the done thing, without realizing what they're paying for (and that they're not utilizing the unique features of EC2).