I have a 3DTV, and it is quite amazing to watch with 3D content. It requires active shutter glasses (albeit stylish and lightweight) to be viewed in 3D. A phone, however, would really need a true, glasses-free 3D display in order to be viable. That technology is difficult to perfect... and it has been worked on for years.
Research and development is costly; a 3D phone would have to be a raging success in order to make the first penny of profit for a company. So far, as Hadron pointed out, portable 3D devices have been mildly received, at best.
All we can really do is watch the Mobile World Congress and Consumer Electronics Shows to see what's coming.