I don't know if you know already, but Tolkien was interested in astronomy, he made sure that any astronomical details were correct in his books (like moon phases and the time of year constellations would show). I also have a keen interest in the area (I have an honours degree majoring in Astrophysics and a Masters degree in Astronomy).
He even mentions Numenorians on towers seeking answers from the stars (or words to that effect).
So, I figure my Haradrim are working for one such dark Numenorian (though I don't own any of the dark Numenorian models) and the reason I chose the scorpion for their figure-head is because they identify with the constellation Scorpio. Traditionally Scorpio is at odds with Orion, which Tolkien mentions as the Swordsman in the Sky.
I figure the astrology/astronomy of this particular Numenorian/Haradrim lord has identified a hero in the North that the Scorpion needs to sting =)
So, to that effect, expect to see some astronomical type things on banners and what-not. First up we have a little balsa-wood easel with a star map on it of Orion. I've been a bit crook recently so haven't done more than this.
Firstly a distance shot so you can see the size. Sort of big, but also not too large, fits in under where my missing strut was.
Terrible photo, but you get the idea. There is some script next to the "belt" as well as next to Rigel (the big blue star) and Betelgeuse (the big red star).
Hopefully I'll be feeling better soon. Got a uni assignment due on Monday, so might not do much model work, but just want to do a banner or two to finish the Mumak off, then it's off to paint a heck of a lot of Harad models!