How to do you open-source a development tool? (Score 2, Interesting)

I have developed a next generation build tool, a make replacement, called KJam ( http://www.oroboro.com/kjam ). I am having some success licensing it under a traditional 'closed' license to software development companies.

I have received interest from some large open source projects to switch to using kjam as their build tool. The problem is that since they are open source they can only allow development tools in their toolchain which are themselves open source. Since they give all their users the right to build their software, they can only use tools that their users are also licensed to use.

Clearly I would love to make it possible for these projects to be able to use kjam as it would be a tremendous endorsement. But if I do that won't I need to provide such liberal licensing terms that I would be unable to continue to sell commercial licenses?

I have seen some open source software projects succeed with 'dual licensing' where the product is free for non-commercial use, but requires a license for commercial use ( e.g. license required for integration into your commercial product like trolltech, or commercial licenses required for some applications or configurations like mySql and Asterisk ).

Are there open source licenses which would be liberal enough to allow other open source projects ( and their users ) to use my build tool and still give me an avenue to sell licenses to large corporate software developers?