Nope, not from the store as far as I know...
There is a feature request for this, but not a single follower :
Restart phone app. It will be easier just to tap a live tile to restart or shutdown phone. ?€“ Feature Suggestions for Windows Phone
If you are a dev and/or can sideload apps, then this might be what you are looking for :
Restart or shutdown v1.0 - xda-developers
...although it is for WP7, it might also support WP8...
Anyone got a guide or step by step on how to do this? the sideloading thing
i have one that i use to get the developer's preview, what do i do after