Is there a roadmap to what is contained in 1.6.5 or 1.7?
This is a feature that will more tha likely be implemented in 2.0. For this logic to be implemented in a fashion that is scalable and flexible to hit all needs, this really needs to be plumbed at the base level...so instead of trying to throw in a patch, it is a design consideration as we start implementing elements in the next major release.
Within our medical system, we have a number of areas that we have implemented some type of caching to reduce hits to the server, but this has generally been added on an as needed basis versus at the core level of the framework.