I have programmed an app for my own usage that I want to share.
It's simply a sticky notification showing wifi state (including SSID and other information if connected) and also if clicked, it changes wifi state.
Hope you find it useful!
You can install it from the Amazon Appstore or downloading the attached apk.
Version 2: Now shows an icon in status bar when wifi is on (connected or not)
Some more info.
Version 3: Auto update (on/off and time interval configurable), icon when wifi on configurable, text color and info in notification configurable, bugfixes.