Well another thing that nobody has seemed to comment on yet is the fact that some of the pieces haev probably already been lost... I mean they've been going on for 35 episodes now and qutie a few people have been captured or killed....

I will take up the stance that Dullindal is on neither side, just playing the game both ways, and is rooting for Black to win....

Shinn as the Black PAwn,
Rey as a current Black Pawn- later probably a Black Knight-,
Lunamaria- BP,
Heine- fallen BP,
Yzak - Black Knight? Just seems like he has some importance more so than the others... but maybe just another BP like...
Deakka- BP
ZAFT Command Station - Black Rook
Minerva - Black Rook, although I could see him having Talia as the Black Queen, however..
Mia Campbell - Black Queen- just because she is so politically important (being able to move in so many directions and so far) And her beign parallel to Lacus
Black Bishops- .......? No real ideas here... Dullindal seems to be the most Bishop like, although I can also see the Junius 7 droppers as a Bishop, due to the fact that I still believe he orchestrated the colony drop, not Logos or EAF, and their sly moving pattern being such. In that case it seems that at least 1 Black Bishop has fallen.

Black King - His cause? PLANT? ...maybe himself? I dunno how this guy thinks...

As to speculation on how Dullindal fits in with Logos, I think he is connected with the company aspect of Logos, but not with the Blue Cosmos. ZAFT Coordinators probably have better engineering smarts than the EAF (ZAFT did invent the mobile suit, makes sense that they'd be the best at creating new units) and I wouldn't be surprised if Logos put aside the fact that he is a Coordinator in order to acquire that much needed military technology.