This has never been discussed before, and as far as I'm aware no one has expressed any interest in working on it. Furthermore, rockbox is probably a pretty poor fit for a TV since it has none of the features generally associated with either classical TVs, nor newer internet enabled devices. That said, if you're interested in working on a port, please feel to grab the source and get to work. Once you do, you can add information about it to the wiki, and start a thread about your progress in the proper forum.