http://smile.amazon.com/Upstar-P55EWX-55-Inch-Definition-Wid...
That's at the budget end of the spectrum, but there are non-"smart" 4K TVs among the better brands as well. This site has reviews of several low to high-end 4K TVs:
http://www.whathifi.com/products/tvs/4k-tvs
Or, you could get a 4K computer monitor, and an HDMI splitter to port the sound over to your surround system. There are always options.