I could help you better if you had an idea of the equipment you will be controlling or reading to/from. Are you planning to totally customize a system or are you looking to use instruments/controllers already available for Home Automation? Im not sure I understand what you really need. Here's an Idea. Computer is the controller of the system.
System consist of Light Control Only (to keep it simple). Program written in LabVIEW. Here you can create schedules to turn lights on/off/dim. Then LV could communicate, (for example using X10 or other protocol), commands to the device actually controlling the lights. Lighting device could be controlled using some sort of communications like, X10, Serial, IR, RF, Ethernet, etc... So this system can turn lights
on/off/dim% either at the click of a button on your screen or a timer. Adding any other system in the house will more than likely require a different communication protocol and complicates things even further. You could much of this with regular automation hardware from NI but this requires integrating different components like relays, dimmers, etc.. Much more work and more expensive, (I would think), than buying a device made specifically for the system.
I hope this helps.
