This newly released Intel NUC looks interesting, 4k graphics & 7.1 Audio via HDMI, over £600 on amazon.co.uk though, and no Operating System, DDR memory or HDD/SSD for that price!
http://www.intel.com/content/www/us/en/nuc/nuc-kit-nuc6i7kyk-features-configurations.html
http://www.intel.com/content/www/us/en/nuc/nuc-kit-nuc6i7kyk-features-configurations.html