I happened about the newspost by Knightwing at Unicron.com, regarding a new image of the third Dairycon figure...
Cool... but wasn't there an unreleased Dairycon Brawn on eBay a while back? I didn't see a picture on any of those links, but the description sounds like him.
Here's a link to that completed Ebay auction of the Brawn repaint. So, we officially know the name of one (the Pizza Delivery truck "Domino"), and have seen two others.
Last day to register for Dairycon. If you want any chance of getting these figures (without turning to eBay), you need to register now.