I think that there should be a way to make a billboard or signs like that. (I am new in Empire Craft so if you can do that could you please tell me?)
There are theoretically a few ways. One would be signs, which would be hard to read at a distance, and they unrender because they're entities. Another way would be regular blocks, which would be very low quality unless they're huge. A third way would be with maps, but those would also unrender, just like signs, and they could start causing lag, so I think billboards can't be added.
What I mean is that you could like advertise or just make something for fun on them and they could be pretty big.
The best way to do what you're saying is through maps. There's a good post on the Empire Blog here: http://empireminecraft.com/blog/tips-and-tricks/design/782-guide-to-minecraft-map-art/
you could do it with woolart. i did that once to advertise my (non-minecraft) website. made a huge ad out of wool on my res.
Azoundria's market portal is kinda of a billboard and also the new command to list all tags is also kinda of a billboard Azoundria's market portal: http://www.azoundria.com/emc/market/?ref=banner&u=2292162809