Well probably not "the" unluckiest, but he does have the 3rd lowest BABIP in baseball (for players with >350 PA, data from fangraphs).  His BABIP is .226, just ahead of General Soreness and Jay Bruce.

While Quentin does seem to have a predilection for low BABIP (his career BABIP is .259 and last year it was .280) .226 is unsustainably bad. Well what should his BABIP be? Fortunately THT has a xBABIP calculator:

http://www.hardballtimes.com/main/fantasy/article/simple-xbabip-calculator/

Plugging Carlos '09 into the formula we get an xBABIP of .286 as opposed to the .226 he has. That would have given Carlos 16 extra hits, raising his BA from .232 to .268. Depending on how many of those were doubles we're talking about a 70-80 point increase in OPS. So .820 or so instead of his .747 OPS.

The caveat here is that Carlos seems to have consistently low BABIP that are sig. lower than what xBABIP would predict. As an example '08 Carlos had an xBABIP of .300 but a real BABIP of .280. So maybe Carlos has a "talent" for low BABIP that the model is unable to pick up or maybe next year Carlos will fall right into his xBABIP. Or maybe the next iteration of the xBABIP calculator that Carty and Dutton are working on will model Carlos better. 

Obviously the difference between .286 and .226 is much greater than the difference between .300 and .280 and so I think the evidence points to Carlos being quite unlucky this year. Even if you regress his BABIP to his career .259 BABIP you get significant improvement  ( 30-40 points of OPS).

So Carlos probably should have had an OPS somewhere between 30-80 points higher than he did.

 I think we can conclude that while Carlos probably wasn't "the" unluckiest player he was quite unlucky and that indicates a better year is in store for next year. However,  in order to return to Q! status he will need to bring his walk rate and HR/FB back up to '08 rates.