Well, I've always seen Amestris as a big mash up of the northern european countries. And Xing, of course, has always been associated with the far east to me.
I used to think Ishval was the mid-east... but now I think they're more of an Indian/Persian mix, personally. Because I actually think that Xerxes is the mid-east equivalent. Yeah yeah they all have blonde hair, but I'm a fair haired/pale skinned/blue eyed arab and we're hardly a rarity. Also, looking at volume 19, you can draw so many comparison with Xerxes' architecture and the typical mid-east one. Not to mention the desert setting and the clothes. (Right, right, also similar to the Ishvalans' but thats besides the point)
Hmm ok, well, if we say that the period in time when Hoho was a slave is the parallel to when Alchemy evolved in the mid-east in our world, it makes sense, right? The actual word 'Alchemy' does comes from the arabic word 'al-kimia' (which in turn derives from the greek word chimia or something, but hey, all words are somehow connected to ancient grecian). This is a big difference to Ishval, where they actively shun Alchemy, whereas innovations in Alchemy was mostly centred around the Mid East in medieval times. Plus, if we think of it geogrpahically, and if we think the entire world (ours) has been condensed on to one continent in their parallel, then the big stretch of desert between the west and the east has to be something, no?
If we're solely discussing this based on skin colour etc, even then I don't think the Ishvalans are mid-eastern. Arabs are generally seen to have olive skin or something.