Actually in the manga I beleive Ashura is an it 
for the majority of the time.  Sometimes more 
female seeming and sometimes male.  I think of 
Ashura as she, though, as seems to me female side 
is stronger.  

Even in CLAMP drawings, they have one w female 
characters and one w male.  Ashura is in both of 
them ;-)  In the female one Ashura is near the 
front, in the male one Ashura is in background.

I've have a few RG Veda cels in my gallery
http://www.geocities.com/ice_at_jla/rgveda.html

And a Clamp in Wonderland one with Ashura also
http://www.geocities.com/ice_at_jla/clampinw.html