Monthly fees for LimeWire or buying it is no longer an option, since it is open-source and any effords to publish new versions as closed source would probably just result in a fork of the project, since LimeWire can't just un-gpl the open versions.

I would suggest the LimeWire developers seriously start working on LimeWire extensions like GroupWare features, much more customizable XML-schemes and some kind of version-control system, so they can sell it to companies. People who don't respect copyrights usually don't pay for software, so gnutella users are no good customers.

To tell the truth, gator/ezula/whatever is the only way to make money with software like LimeWire and I was already wondering how a company can survive for that long without making profit of some kind.