Now this is one interesting concept for a VR peripheral. These computer-controlled stilts are called "Level-Ups" and simulate stair steps and give a sense of elevation while standing on virtual objects.
Made by a group of engineers at the Hasso Plattner Institute in Germany, they also created a funny comparison video with Garry's Mod to show how it works:
It's probably more useful for motion capture than walking around the living room. Because something like that could end horribly.
Each Level-Up unit is a self-contained device worn like a boot. Its main functional element is a vertical actuation mechanism mounted to the bottom of the boot that extends vertically. Unlike traditional solutions that are integrated with locomotion devices, Level-Ups allow users to walk around freely ("real-walking"). We present Level-Ups in a demo environment based on a head-mounted display, optical motion capture, and integrated with a game engine.