Been experimenting with independent module versioning by developing an OSGi IRC bot. The idea is to expose any deficiencies in tools when modules within a single Maven project have different version numbers.
Initial indications are good!
One serious issue is that with independent versions, sooner or later there's going to be a release of the project where one or more modules haven't been updated and will therefore have the same version numbers as existing already-deployed modules. It's therefore going to be necessary to work out how to prevent Maven deploying bundles that already exist. Apparently, Charles Honton has a plugin for this.
Conceptually, moving to independently versioned modules means that a given project version now describes a set of module versions as opposed to simply defining a single version for all modules. I might rewrite changelog to better fit with this fundamental conceptual change.