Well, I would like one and since I'm un-experimented with all kind of 2D design, if you could make me one, I would love it!
I don't want anything too big nor too small (the size of your sign seems well). For the colour gradient, I would go for something like the AVP Galaxy banner to 'cloak' with the forum and don't hurt too much the eyes.
Rectangular shape.
I would like one of thus item:
-Elder Predator
-Giger's Alien
-Acheron or derelict for background.
Then if you want to add personal touch, feel free to do it, I don't want too much restriction, it's better to let the artist handle his project alone.