The 4K resolution boom is fast approaching and current technology is simply not ready for it. You already see half attempts at using 4k resolution in "IMAX" theaters that use standard sized movie screens to improve clarity. The PC market is always prepared and is three steps ahead of the game. The new ASUS Z87-Deluxe/Quad are now certified with Intel Thunderbolt 2 and I will explain how the two relate.
The Thunderbolt 2 spec is not physically different from the original, but utilizes resources better. The original Thunderbolt has 4 channels (2 up and 2 down) that could carry 10 Gbit/s each independently. The new Thunderbolt uses these in pairs for 20 Gbit/s and makes them bi-directional. That gives these ASUS boards the ability to stream 4k resolution content to up to three 4k UHD displays.
This is just the beginning with the ASUS Z87-Deluxe/Quad. Not only does it have two Thunderbolt 2 ports (supports daisy chaining, DisplayPort 1.2), but comes with some great new features including NFC Express, NFC Remote, Wi-Fi GO!, and Dual Intelligent Processors 4 for easy tuning.
There is currently no price listed for the Z87-Deluxe/Quad, but I am sure it will not be two far north of the current Deluxe/Dual at $314.99.