Started here
http://arduino.cc/forum/index.php/topic,78631.0.html
Really started to get small around page 6
More here
http://arduino.cc/forum/index.php/topic,88454.0.html
I still have 5 left from the batch of 20 I ordered. I should try putting one together now that I have refllow capability.
Don't think I ever ordered any 32u4 processors.