Well, this is a yes and no answer.
I would encourage you (and others) to consider submitting a Wish Form to ask Adobe to put this on their radar for a future version.
If all your video topics were all part of the same RH project and no other topics formed part of that project, you could do this by amending the skin file to display a different icon. It would require a merged WebHelp appraoch. The WebHelp skin defines the icon to use throughout the whole project so it would be an all or nothing approach for each project.
Thanks so much for your answers! I submitted a suggestion for future versions, too.