Not sure if Id trust retractable cleats. Would be afraid theyd come loose and would wiggle and rattle like crazy.
Good news - you have options:
If you use Look pedals - you can get cleat covers for them that will allow you to walk on any surface and not scratch them up. Also makes it easier to walk on. You only have to slip them on or off. theyll easily fit in your jersey pockets.
For SPD pedals, they make cleats with plastic 'pontoons' that are thicker than the metal cleats. I used these with my SPDs, and was able to walk on cement and hardpacked sand no problem.
