Just yesterday, there was a new report confirming Notification Center in the upcoming Windows Phone 8.1 update in 2014. Apart from Notification Center, Windows Phone users also miss the ability to quickly access the settings like Bluetooth On/Off, Wi-Fi On/Off in notification center. There is a new app in Windows Phone Store called Kirik Settings which allows you to quickly access settings like Wifi, cellular data, location, Bluetooth, etc, from anywhere via volume controls.
There are lots of other quick access apps in Windows Phone Store that requires you to pin them to Start screen to make use of it. But this app can be used anywhere from the OS. There is an important limitation when using this app, it stops working if you play music. You have to re-enable it to make it work again!
This app costs $1.99 with free trial that allows you to experience how it will work. Find the app here in Windows Phone Store.
Thanks to Arun for the heads up!