I finally got some time to goof around with the terran defense build.. it works in 3v3, if nothing else. I have one of the most fun 3v3s I've ever done using it.. Me, an OK protoss and a terrible terran against 3 decent enemies. My favorite point in the game was when I fought off all three enemies using a combination of my expand's planetary fortress and some thor.. I ended the game with twice everyone else's score.
But I did it three times, and all three games we won. None of them were against pathetic opponents either.. though I will admit that a few games ended before I could do much with my insane economy.
The build i was toying with went something like 9 depot 10 gas 12 rax, 14 engineering bay, 15 or 16 gas.
Right as the eng finished, i had enough gas to build the gun. I think i got 400 right around the time the gun finished, started a second command center touching my first one, research range increase, factory, 1-2 AA turrets... then it kind of diverged. the second com also got a PF, and my econ became absurd.. I ended up doing heavy thor most of the games, but I also did viking/banshee. Both worked well. It works way better against zerg and protoss.. somewhat dangerous against terran.
Unless both players were doing the same build, it wouldn't work well in a 2v2, but in a 3v3 or 4v4, nobody expects it and its really fun to do.