Thinking of it there used to be an application pisibul that pointed at svn to build packages from source.
I bet it could be changed with little effort to point at a specific repo. Or from scratch in qt based on package-manager but seperate and not linked to so that people know they are using unsupported community packages....hmmm
That way users could be warned and would use a specific application for building community packages.
/goes off looking for source code for pisibul/