Far as I'm aware, there isn't a "real" artbook for Luminous Arc yet. Those thin-book preorder extra's don't count: they don't have all the concept sketches and color spreads. Maybe some day in the near future, but for now, zilch.
The pic comes from the official Japanese guidebook for Luminous Arc 3. Yeah, yeah, yeah... I know Fatima is from LA2, but they made this special spread for the LA3 guide.
Fatima is fan favorite of the series. And let's be honest, can you really argue with that? If Roland didn't pick her over Althea, he's an idiot.
At least Fatima has an ending. Or when you said "didn't", did you mean by the ending not being cannon?
Let's be honest, I know a large number of the players (I'm one of the FAQ authors at Gamefaqs) who were drawn to Fatima's breasts first before anything else. Guess we should be happy Althea isn't as endowed? XD