Adding custom GUI to a DirectX 9 App

Basically i just want to add something like the taskbar to the bottom right of any fullscreen directx9 applications/games, something like the date/time.

Just wondering if its possible and how i would go about doing it, this is what ive guessed so far:

Hook the direct3d device
read content of the front buffer, draw on to it, and update the front buffer? or just draw onto the front buffer without clearing.

anyway, if anybody has anything that could help me out it would be appreciated.

thanks