I think it's either white rice or the white potato. This time last year people still thought that sweet potatoes were paleo and white potatoes weren't. (I'm aware I'm being a little bit provocative with that statement. But just a little.) And the rise of Perfect Health Diet (no "the," like Facebook) has brought with it a huge increase in the amount of rice consumed by paleos.
Offal (especially pastured liver) is a super-food that would win every year's contest, in my opinion.
However, if we're to just speak only about trends/fashion, I think the breakfast muffins have been a hit with Paleo dieters recently. Reddit's r/Paleo section was full of pictures from people experimenting with these lately! Tumblr's Paleo tag search revealed a lot of such pictures too. Their appeal is that you make many of these ahead of time, and then you have microwaveable breakfast for days ahead. I put a recipe up with these too (as many other Paleo bloggers did too): http://eugenia.queru.com/2012/01/18/breakfast-paleo-muffins/
I agree 100% with WCC Paul, white rice and other starches and more fruit. Granted I train several hours a day but adding more carbs (and personally, I do much better on white rice than sweet/white potatoes) did sooo much for my training, recovery, mood!!!, satiety (I could drink cream like water and still wanted more on my high fat diet) and even leanness.
This....I know its been around longer, but I just found it in 2011 and that's all that counts :P .....http://www.grasslandbeef.com/Detail.bok?no=821 .....mmmmmm, liverwurst all the goodies in one package.
Not a specific food exactly but there has been a lot of fermentation love online this year. Kraut, kombucha, kefir - all great stuff and all getting a little more of a shout out in 2011 (my view at least).