Mysterysmith. I know what exactly you want. Do this,
Either make your own 2 D animation clip or download it from the net. See that it should be small.
Then, split that animation clip into frames or images using softwares like VirtualDub.
Then, using Terranim8or's animated background feature, display the sequence of images in anim8or.
Refer terranim8or's tutorial page for 'How to do it".
Remember, to achieve the effect you want you need sequence of images that will be displayed on a stationary board. So, this can be achieved with a short code, which the terranim8or generates for us.
However, if you want to generate just a simple moving message like a scrolling text, you can do it in anim8or scene mode itself by turning the object's visibility on and off.