It's still a big mystery why Sony chose not to make controllers with 'force feed-back" for the PS3, but it seems that someone has taken a closer look into the problem and has made an attempt to fix it. The guys at SplitFish are the ones managing the works on an invention they call the "Sensor FX feedback system" and it is a device similar to the one they made for the PS2, the "Motion FX" for the dual shock controller.
The Sensor FX was created not only to fix the PS3 controller's problem, but also to bring low energy consumption through sensory feed back. The Sensor FX is not as "violent" as classic vibrations, but it has the ability to derive feedback sensations from isolated areas on the controller, to isolate one side or the other, movement from front to back or all areas at the same time.
In simpler words, nothing like vibrations, which - if you ask me - will never be replaced by anything else that doesn't work with magnets. Oh...the device probably does have some but I haven't seen the specs yet. So, how exactly does it work?
The perfect example is that of a gamer playing a race game. Having the Sensor FX enabled, he will be able to feel variations in pulse, strength and collision location and to feel intensity differences between smaller or bigger impacts/collisions with the surrounding environment.
So, while SpliFish is trying to solve some of Sony's booboos with pretty innovating work, the Sensor FX they've created won't even be close to the force feed-back players that can benefit from classic dual-shock controllers.
PS3 Controllers Get Force Feed-Back
Not exactly vibrations, more like sensations...