How about if you add a custom resolution of 720x576 (or 720x480). If you match the aspect ratio of the resolution to the aspect ratio of the TV, you should lose the bars.
800x600, 1024x768 etc on my TV always leave bars at the top and bottom (or zoom and crop left/right off).
nVidia cards with integrated TV-Out encoder (rather than Conexant encoder) also have the option of zooming full screen video to fill TV-Out, but I think this only affects overlay, not the VMR renderers. It can be set through the registry (NVZORAN625@50Hz.videoborder and NVZORAN525@60Hz.videoborder). Set to 00 to let it zoom full screen overlays to fill TV-Out, or 01 to let it use your custom overscan settings.
800x600, 1024x768 etc on my TV always leave bars at the top and bottom (or zoom and crop left/right off).
nVidia cards with integrated TV-Out encoder (rather than Conexant encoder) also have the option of zooming full screen video to fill TV-Out, but I think this only affects overlay, not the VMR renderers. It can be set through the registry (NVZORAN625@50Hz.videoborder and NVZORAN525@60Hz.videoborder). Set to 00 to let it zoom full screen overlays to fill TV-Out, or 01 to let it use your custom overscan settings.