I like this idea, but JetBrains is a much bigger company and is probably in a better position to be able to afford to do this. Unfortunately the type of person who has a strong enough interest in using NCrunch for unit testing is also likely to be the type of person who would volunteer on an open source project. You could argue that the main source of finance for NCrunch should come from companies purchasing it for their development teams, but personally so far I haven't had any luck convincing the companies I've worked for to pay for it (especially as there's a test runner in ReSharper).

(Note that I don't work for the company and have no idea what their finances are like, however I have used NCrunch since it was a free beta and I'm a huge fan)