Originally Posted by Schlachtwerk
I think this is not possible on AGA.
Why not? The smooth parts of the color gradients in the color bars were opaque so you could disable the display DMA while they were being displayed to get fast copper. The backdrop would probably be blitter-based. The moving text in the middle would be sprites and therefore would be unaffected by the display DMA being disabled for the color bars.
I say it's perfectly doable on AGA. It's even possible on OCS if you didn't have the smooth color gradients used on the color bars.