I'm watching Qlikview do this right now - their original product was and still is a client app for Windows. It allows any business user to pull through datasets of pretty much any source as a poor mans ETL, then it allows that user to do BI tasks in a very simple way. Where they are succeeding is that they haven't given up on this market, but are using it to drive interest from inside companies - eventually skunkworks divisions show its value to the business, which then buys the server software and licenses.
It's growing pretty rapidly, and they seem to have a sustainable model. But it's driven by the individual user.