We consider a generalisation of the DGP model, by adding a second brane with
localised curvature, and allowing for a bulk cosmological constant and brane
tensions. We study radion and graviton fluctuations in detail, enabling us to
check for ghosts and tachyons. By tuning our parameters accordingly, we find
bigravity models that are free from ghosts and tachyons. These models will lead
to large distance modifications of gravity that could be observable in the near
future.Comment: Dedicated to the memory of Ian Kogan. Version to appear in Classical
and Quantum Gravit