What sort of control systems do I want to apply to my off-grid house?
There are a lot of controllers available on the market which deal with individual parts of a household energy system: battery charge controllers, solar thermal pump controllers, and so on plus all of the controllers built into individual devices such as refrigerators. However, these tend not to take a very "holistic" view of the situation; the operation of the fridge does not depend on the state of charge of the batteries, output of the PV panels or the amount of wind forecast for the following night.
In particular, management of the the thermal store requires careful consideration of the expected weather over the next few days. Putting extra heat into it during a hot spell in summer does not make sense as it will only make the house uncomfortably warm whereas any energy available needs to be jealously guarded in winter.
Rest of control
At least part of my thinking here is that there might be an interesting consulting business to be built around the use of open source software and hardware for more sophisticated energy management systems for off-grid and similar houses.