Also:
http://forum.shrapnelgames.com/showthread.php?t=35105
http://forum.shrapnelgames.com/showthread.php?t=38342
As you can see, we came to a conclusion that the EA nation should be mainly genie-based, with primitive desert nomads as sidekicks (and yes, I agree that they should be raiders).
MA I think should be something like 10th century Arab states of Middle East - with both city and nomadic troops, plus ghulam slave warriors. I used some Persian patterns in my version (Pekhlevans, etc.) though I'm not sure now these were quite in place here.
LA was based on Ottomanic Empire quite shamelessly.
Unfortunately, we had a pesonality clash
and this stopped to be a common project. Still, I have MA & LA almost complete except for pics. Look them up (the 2nd link) and say what you think.
Also. Of course, genie should be summons outside of EA. By the way, genie in my variant are also partly Persian - mainly because I have more sources on them. Genie locus I like, but am not sure about where it comes from. I remember genie countries in 1001, but these usually lay "at the edge of the world"... Also, after-Mohammed times should get both faithful genies and infidel ones. I think that the latter should be mages with more broad skills (and maybe slightly more levels), but the former retain priestly powers. In EA there should be no such division.
Considering heroes - I am not sure about EA, but for MA/LA I made Old Man of the Mountain (heretic who still domsummons his disciples - it's up to player whether to keep him at home or use to undermine enemy...
), Hoja Nasreddin - a Middle Asia folklore character with some cool abilities, plus, of course - Abd al-Hazred (someone should write Necronomicon)!
I am not sure what to do with Khaliffs - they can be multiheroes, or prophets... Ideally, they should have high H levels, be present one at a time, but be replaceble if one is killed. Recently I saw an idea to highjack, say, Abyssian prophet for such a purpose. Unfortunately, this makes a mod not usable together with some nation in basegame (maybe it's possible to use unit from another era, though).
Also a question - how good are you with pixelart? I made some attempts at this and am ready to allow my pics to be used in your mod if you allow the same (not sure whether you need mine, of course
). I think that Aezeal will also allow to use his pictures, but you better ask him, of course...