D-Link's new Covr Wi-Fi system has a range of to 6,000 sq. ft.

The Covr AC3900 Whole Home Wi-Fi System is a simple, intelligent solution that uses a high performance router and seamless extender to create a single network with ultra-fast speeds and reliable connectivity, that can provide up to 6,000 sq. ft. of Wi-Fi coverage.
D-Link’s Covr AC3900 Whole Home Wi-Fi System uses a premium AC2600 High-Power Wi-Fi Router at its core, creating a Wi-Fi “PowrZone” of blazing fast Wi-Fi, optimized to handle the bulk of your activity, while the Covr Seamless Wi-Fi Extender takes care of the outer edge. This design ensures you get whole home coverage, while still having the power, speed and advanced features to handle bandwidth intensive activities like 4K streaming and gaming on multiple devices.