Think of the word "oriental" in keyboard,
the same as in "oriental" carpet. It is
referring to Middle Eastern countries, and
not to Asia or countries East of Asia.
In my opinion, an "oriental" keyboard or
at least "oriental-capable" keyboard must
have(or at least have the capacity to have) all of the following:
1)Middle Eastern (oriental) Soundset.
This includes oud, kanoun, mizmar, nay,
2)Arabic (oriental) Drum Kit.
This includes arabic tabla AKA darbuka
AKA doumbek, zills AKA sagat,zaghruda AKA
zaghreet (these are screams),riq, doholla,
bendir,deff, dawul, etc.
3)Microtonal Tuning Scales.
The basic designated "oriental" models
have a 1 octave button set where each
activated button lowers that note to a
fixed 1/4 tone (-50 cents). More flexible
keyboards (those usually not designated,
but "oriental-capable")have a range of
microtuning for each note of an octave
(for example +/- 63 cents), so you are
not limited to just -50 cents.

I am trying to put together a list of "oriental" or
"oriental-capable" sound modules. Could
any of you please help.
So far, I have:
Korg i40M