The rare SEGA collectible that is the Dreamcast Dreampoint Casio Portable TV is a lovely little retro gadget. It also, quite obviously, is a TV.
Said TV was given (only in Japan) as a reward for collecting 10,0000 Dreampoints. It is a (for the time) high-res splash-proof little thingy, that's easily connected to a Dreamcast (or any console for that matter). This 12-ounce, 2.3-inch-screen TV offers color viewing for up to four hours on four AA batteries. It also has the capability to receive both VHF and UHF channels.
You can grab it via this Dreamcast Casio Mini TV eBay auction. Seller ships to America, Europe and Asia. It comes with the original strap, an AC Adapter, the instruction manual, the Dreamcast connection manual and some other papers/flyers.