pretty much anything is possible, as far as just the idea goes.
The real issue is the qualities of the material.
You have to consider that for such a suit you would need a hell lot of very small mechanical parts that have to hold out a lot of stress, like small servomotors but eventually with immense power behind it. - thats why current power armors only amplify the users power.
I could imagine that a suit for it self, just to build it isn't even the real problem. Certain military and civilian projects already go in that direction (somewhat), just google power armor or type it in youtube, its very interesting how far the technology is already. There is also the idea of artifical muscles that actually have the "potential" of beeing 10 or even 100 times the strength of human muscles. if I remember correctly.
But as far as the stuff goes we see in movies or games and the like, I would not be surprised if the problem here isnt eve nto build that stuff but the power transmission, imagine it as something like Ghost in the Shell, if you remember the scene where the Cyborg is trying to open the hatch of a tank with her bare hands but she ends up tearing her own artificial arms apart because the force behind the muscles was simply to much.
http://www.youtube.com/watch?v=J6fQ4umUW4Y&feature=player_detailpage#t=307
As a matter of fact, our body has a lot of limitations by our brain to prevent our muscles causing damage to the joints which are a natural weak point compared to the solid bones. When those limitations are suspended, for example by someone who has epileptic shock you can actually see what real power the human muscles can have.
A mechanical issue that is maybe known to some with heavy tanks from WW2. Tanks like the Tiger 2, or Landbehemoths like the Maus that would crawl around with 70 tons and in the case of the Maus 188 tons. To get those things to move around wasn't even the problem, its the gearbox and the power transmission that caused a lot of problems, if the Tiger 2 was actually correctly maintained and the driver experienced then the machine was just as reliable like most other German tanks, in other words good. But driving the tank to the limits was a lot of stress because neither the engine nor the gearbox and the other mechanical parts have been made for tanks that had more then 20 or 30 tons of weight, and now you use them for a tank that had almost 3 times the weight. Today this isn't so much of an issue anymore simply because the materials, metallurgy and mechanics has advanced, the way how the transmission works and all that. Thats why the Leopard 2 that has pretty much the same weight like the Tiger 2 can move around with 70 km/h while the Tiger 2 only with 20 km/h eventually.
But I am afraid, that the kind of materials we would need to make a suit, like we saw them in Iron Man, where he can lift cars and who knows what else simply don't exist. At least not yet. And its rather questionable if those materials will happen to show up in the near future. I am really not some expert on metallurgy nor with physics. But there is a certain limit for every material as far as the stress goes, and you simply cant take something like a servo motor build it with the size of a small bolt and then use it to withstand the power of several tons.