We don't accept feature request. This forum is named "feature ideas" for a reason -- it's for discussing ideas, and perhaps you manage to get someone interested enough to actually do it.
As for the idea by itself: I don't think it's likely for anyone to work on that. The first Rockbox logo shown is displayed by the bootloader, not Rockbox itself. That means you need to change the bootloader, and that is something there's generally not much interest in.