Hi jbmusic
I got your point, it'll be a small video icon but will be a bit complicated to achieve. In other templates, we often customize the intro image layout file in com_content for different content type: default, video content type, etc... and in layout file of video type, we will customize the mockup by adding icon there and style for it in module or other layout view on frontend.
This would take time, I recommend you to hire a developer to get this done for you in case that you're not familiar with coding.
Regards