Sharp is the only manufacturer making consumer LCDs 70" or above, so it isn't ecaxtly like you you have a lot of manufacturers to choose from. You can either get their base 80-incher, the 80LE632, which is 120Hz with wifi built in for apps. Their step-up 80" model is the 80LE844, which has a 240Hz refresh rate. 3D, a web browser, and their Quattron technology (adds a yellow subpixel to existing red, blue, and green).
There's been talk of Sharp releasing an 80" Elite model later this year, which may or may not include 4K resolution, and would include an LED backlight with local dimming like the current 70" Elite model (The PRO-70X5FD). None of the non-Elite branded Sharps have a local dimming backlight. The price is sure to be astronomical though. If you arent familiar with Elite line, check out http://www.elitelcdtv.com
to find out more.
Also, if you're looking for BIG, at least take a look at the newly released sharp 90"-er - the LC-90LE745.
ht Panasonic TC-P60ZT60, Monitor Audio: Silver RX6, RX Centre, Radius 90HD; Martinlogan Dynamo 700, Marantz SR5006, PS3, Oppo BDP-103D
2ch Marantz PM8004, Sony BDP-S1000ES, JVC T-X3 tuner, Monitor Audio Silver RX1, REL T3, Apple TV, Peachtree Audio DAC•iT
lr Panasonic 50ST60, Sony BDP-S5100