I've really been enjoying modding mesh attachments and such on my avi for some time now. Recently I've seen a few mesh items with animated textures, like a GIF or something on them. I explored the "Media" setting on the build tools, and I have been able to make an MP4 video loop on a face of a mesh attachment nicely. Only problem: other users must have all four boxes under the Preference>Sound&Media>Media tab of their (firestorm) settings checked in able to see the animated texture.
Maybe I am using the term "animated texture" wrong, as its really video media that I got working.