Is it possible to move the status / notification bar or the settings icon? If I'm using my Smartphone with one Hand (4.3 inch display) its hard to reach the settings button in Android 4. Yes, I'm able to add an icon to the home screen but if I'm using an app this doesn't really help. I need to switch between the screens first.

My idea would be something of the following:

A) moving the status / notification bar to the bottom (lift up instead of lift down)

B) moving the settings icon to the left side of the bar

C) moving the settings icon on the bottom of the notification list

Is there an app available doing this?
As far as I know, there is No app currently available to do this.
You can try CyanogenMod for your device for various customization options.

I have seen options to move status bar to bottom on CyanogenMod 7.2 (Android 2.3.7 GB) port of my device (Samsung Galaxy 3). So it's certainly possible easily on custom ROMs.