In the spirit of letting people really just throw together some real abominations, why not add a #marquee tag that lets you stick a scrolling marquee on your node? I'm not sure how viable it is to move text like that, but if it is, it'd be a cool thing to have.
The way it'd work, in my head at least, is similar to currently-existing markdown tags. It'd have two, maybe three arguments - The width of the overall marquee, the text color, and the text itself. For example:
#marquee
150
red
HAI GUYZ WELCUM 2 MY DETHBALL FAN PAGE xD
#endmarquee
