I can only see it working against Protoss, but I've had *limited* success using fast ghost builds, and probably would do better and keep using them if I spent the time to optimize one. What I did was:
Racks>gas>2 more racks> push out at around 9 minutes or when have 2 ghosts (I forget what the timing on this was - it's been a while) > expand while attacking.
A few good EMP's will really put pressure on the Protoss early game if you have a good force of maybe 12 marine/2 marauder/2 ghost (ideally with cloak). Especially if you hit the sentries before they can throw down those annoying force fields. I've won a couple of games with this, though at the time I was low gold and I'm not sure how it'll go in the higher leagues. I'll try (I should break into platinum this week, I've been top four for a while and winning most of my games) and come back and tell y'all how it goes. :D