Neuros Technology has been making open source video capture and media systems for several years and I have used their Recorder 2 and OSD products to capture TV content and convert it into a format for playing back on my mobile phones, iPod, and PSP. I currently have and use the OSD, which is actually on sale right now for US$149.99 from their store, since it has more options than the older Recorder 2. Neuros recently announced that the developer kits for their OSD 2.0 are now available for US$249.99. These are still labeled developer kits because the software is not finalized and they are designed to get out and in the hands of those who will make it work well for the consumer.
The intent of the Neuros OSD devices is to provide a completely open set-top device for TV applications. Even with the current Neuros OSD you can do things like listen to Last.fm music and check out YouTube right on your TV. There is also development of a web browser and much more.
The OSD 2 has high definition support and provides more than the current OSD, but it is really just for those looking to develop for it at this time.