I think it probably is real- I bought an Eva cel 
of Asuka from a reputable dealer and I'm pretty 
sure mine is real- I've been collecting cels for 
a couple of years and I have acquired something 
of an eye and nose for the real thing - at least 
I think so.  :)  I've been seeing more eva cels 
around recently, I hope this means they will 
actually be officially released in a larger 
quantity.  (or do I?  eeek...money....)  
Having a sketch helps give it credibility, the 
fact that it is not an A type shot-
off centered
eyes closed
and that it is about the price I would expect 
makes me think it probably is real.  
I would love one of the other shots I've seen of 
her on YJ but I can't shell out the money... I 
still love the one I have the best anyway.  ^_^