It's generally pretty well established that a properly executed model release provides a pretty wide latitude of commercial usage--although one can always come up with corner cases, e.g. use of a photo in a context that implies the subject is a drug addict or something similar.
By contrast, there's very little legal precedent around the scope of property rights in commercial photography.
The analogous question is what rights you have to use a photo for which you don't have a model release, and that's where I think things are pretty fuzzy.
See e.g. http://www.istockphoto.com/help/sell-stock/training-manuals/...
However, unlike model releases for people required for commercial (as in non-editorial) use like marketing and advertising, it's a very fuzzy area.