It won't work.
It'll work about as well as "Video Calling" and video clips has on 3G. IE it sounds great until you try to use it, then you realise how crap it is and either walk out the store, remove it from your mobile tarrif or simply never bother to use it again. A mobile screen isn't big enough, and people won't be arsed to carry a dedicated device that is. Witness the almost complete failure of the tiny UHF LCD televisions that have been launched and promptly forgotten countless times over the last twenty plus years - people want their Telly big, noisy and comfortable to watch. Why else do TV screens get bigger and bigger whilst every other domestic appliance gets smaller and smaller? Why is it always the focus of the lounge, opposite the most comfortable chair?? Any clue as to why most people look for smallness in a mobile above almost anything else?
And I don't see there being a mass-market for people standing in bus-cues watching TV. People usually either listen to their MP3 player, or read a book. Or both. "Things to do whilst waiting for a bus" already exist. A book is perfectly at home in a gym bag, even being dropped down a flight of stairs won't render it useless (usually). Try saying THAT about a sensibly-priced mass-produced telly!
There are technical problems, too. Like how to make the screen bright enough to watch in daylight whilst also providing enough battery life to be worthwhile? Since the antenna is non-directional you'll struggle to get bandwith enough to make a good picture. It's not like a mobile - Don't forget you can drop 100th of a second of speech and people just hear a click. Drop 1000th of a second of video data and you loose that frame - video doesn't just require more bandwidth it also requires better QOS.
Finally, the business model itself. Mobile phone companies will doubtless want to charge a fortune for service to "recoup" their 3G expendature - and will almost certainly price the system into failure. Once they've done that it's practically impossible to change the publics perception that a service is expensive - even when you drop the price! Initial programming is going to be cheaply made, so content won't sell it either.
it's a dead duck. It's been done, it's failed before. It'll fail again and merely changing the technology won't fix that. People don't want micro-televisions.