Unified generalized Chaplygin gas models assuming an interaction between dark energy and dark matter fluids have been previously proposed. Following these ideas, we consider a particular relation between dark densities, which allows the possibility o
f a time varying equation of state for dark energy that crosses the phantom divide at a recent epoch. Moreover, these densities decay during all the evolution of the Universe, avoiding a Big Rip. We find also a scaling solution, i.e. these densities are asymptotically proportional in the future, which contributes to the solution of the coincidence problem.
