Producers -- especially "universal" producers such as accountants, lawyers or IT types -- tend to see only one dimension (the market). "I do computer repair. I don't care what your business is. A PC is a PC." Even worse, they tend to see the market in gross terms. "Project Management is a matter of managing projects. I don't care if it is a marketing project, an IT project or a merger & aquisition."
Unfortunately, the customer tends to see themselves in their own dimension. "I need an accountant. He has to be familiar with Dress Shoppe retailing. After all, our tax laws are different."

I haven't seen any other dimension. Most of the other candidates tend to be different levels of detail along one of the two dimensions (e.g. industry vs size of organization). And using other entities (a typical way of determining dimensions) usually just gives a variation on one of the two.
Perhaps skills might? Be an interesting pub discussion.