[mids_hn]

Another approach is a source-available license.

The one I'm interested in would be one, where viewing, modifying, recompiling the source is allowed, but redistribution is allowed only to those who had bought the license from all owners of the source and it's modifications. It would produce a nice "waterfall" effect.

It wouldn't be open-source nor free software, but most people don't really need limitless redistribution, and the source would be proof that said software isn't malicious.