The large variety of devices that are gaining access to the Internet requires novel server functionalities to tailor Web content at run-time, namely transcoding. Traditional schemes assign transcoding operations to theWeb server or single edge proxies. We propose an alternative architecture consisting of cooperative proxy servers which collaborate in discovering and transcoding multiple versions ofWeb objects. The transcoding functionality opens an entirely new space of investigation in the research area of cache cooperation, because it transforms the proxy servers from content repositories into pro-active network elements providing computation and adaptive delivery. We investigate and evaluate experimentally different schemes for cooperative discovery of multi-version content and transcoding in the context of a flat topology of edge servers.