Marius: You might want to consider a proper dual license rather than your semi-open license. The AFPL which is not an OSI-certified license might fit the bill for the "open" part: http://www.cs.wisc.edu/~ghost/doc/cvs/Public.htm, since it limits commercial use. On the other hand, downstream sharing could be accomplished with Freenet's Fairshare scheme (as opposed to a seperate license): http://freenetproject.org/index.php?page=fairshare.
Cheers, Glen Low, Pixelglow Software www.pixelglow.com -- license-discuss archive is at http://crynwr.com/cgi-bin/ezmlm-cgi?3