Maketoys have updated their site with new images and information on their Mobine – unofficial custom take on The Fallen. The numerous sockets around the toy have finally been explained as being Power Core Combiner sockets – Mobine when transformed forms two tanks, evidently one of them becomes a mass of guns and other weapons that can attach to Power Core Combiners using their combiner ports. Presumably looking at that last colored image the weapons also combine to form limbs for a main figure, which we are assuming is the second tank that has been shown (yet to be seen in color).
As for the colors, Maketoy has diverged from the usual Fallen style of black and brimstone for a more military deco. Perhaps like their green Giant a black version will eventually follow.