Is it possible to remove or hide the title bar from an Outlook custom task pane? If so how. If not, maybe using a hack? Using a hack, how?
There is no trivial way of getting the job done. The Outlook extensibility model doesn't provide anything for that.
You can try using Windows API functions for subclassing Outlook windows and injecting your own form in Outlook using the SetWindowsHookEx function. Read more about that in the Hooks Overview article. This technology is called adjucent windows in Outlook.
Also you may take a look at Advanced Outlook view and form regions from Add-in Express.