SAO Launcher is a menu that can be opened anywhere by swiping down from the top left corner. Get access to sms, contacts, apps, and more regardless of which app you're currently in. Ads can be disabled with a $4.99 In App Purchase inside Options, which also unlocks some additional features. v2.3.1 is for Android 2.3, which is no longer supported. v2.6.1 is for 4.0+.
The Sms Extension module lets you reply to sms inside the app and (optionally) receive popups when you get an sms. Just install it and SAO Launcher will do its thing.
The KitKat Theme changes the entire look and feel of the app, including the images and sounds. More themes and extensions can be found inside the Store in SAO Launcher.
You can watch a video of it in use here.