There are a few you can actually buy now and about 10 or more by the end of the year. For now, you just have the Sony/LG/Toshiba 84" 4K LCD all using LG Display IPS 84" 4K panel. Price range from around $15,000 - $22,000. A lot of that price is sheer size than the 4K tech. Samsung has 85" 4K for $30,000. Seiki has a 50" 4K for $1300. Sharp and Toshiba have a few 4K but they are over in Japan.
Now for a few that should be available by the end of the year. LG has a 55" and 65" coming around for around $4-5K. Sony also 55"-65" 4K using AUO panel at probably slightly higher $5-6.5K. Hisense will have a few also. They will probably have the cheapest 65" 4K at around $3500. Next year you should see more manufactures offer 4K and prices to fall rather quickly. Especially since the PS4 with 4K playback will be out by end of the year.
DON'T ARGUE WITH ME. I AM NEVER WONG.