Entrepreneurs are thinking about exit strategies earlier than ever before, according to small-company merger-and-acquisition consultants. Some founders are even creating business plans with one type of buyer in mind -- say a large-company strategic partner. This is a big change. When we surveyed Inc. 500 CEOs in 1986, for example, most had given little thought to selling or passing on their business. One explanation for the change: founders are better educated about company building. Another reason, says one consultant, is that more people see starting a business as a means to an end, not an end in its own right.