We all know one of the limiting factors within thr VR world is being able to move around the environment. Sure with room space you can move around within a limited play area but then when you want to move you character a lot of games use a similar point and teleport method which looses a lot of the immersion. We have seen a few vids of running style machines, but these simply aren't practical for 99.9% of home users.
What I suggest are some very small, low powered ankle straps/bracelets that a player would strap around each ankle. Each one has several IR leds and a small battery and that't about it. Because you are only powering LEDs it won't need a massive battery (which should be rechargeable).
Then for a player to walk around, they would hold a button down on the controller and then simply walk or jog on the spot. You need to add the button on the joypad so the game can tell when you are physically moving vs looking around using room space (which also still allows a degree of walking around).