Like Brian mentioned, I know one building owner that uses the Tuxedo Touch with Z-Wave thermostats to control environmentals. There's no reasons they couldn't do some lighting control, as well, aside from the fact that they haven't gotten around to changing all the switches. It works well, from what I see, but it's not a big place.
For larger commercial environments, you'll need to invest in systems like Crestron or AMX, but they won't make most of the actual lighting controls themselves, instead integrating to third party stuff (aside from some switches) and they won't come cheap. But, they'll do absolutely everything you want them to do. Becoming a dealer won't be easy, either, for either of them, unless you already have an A/V department.
You likely need to control things at a circuit breaker level, as many offices don't have light switches for the common areas. I also liked these systems for doing cool things like shutting down audio/visual components, setting back thermostats, and turning off the lights when the system is armed. It can also turn them back on should it go into alarm. That's where integration gets fun!