Yeah you can build a suit... in 2010. It's possible. All you really have to worry about is power source and flight.. Exoskeletons has already been invented so all you really need to do is downsize it. Power source.. A way to get started is you're gonna need a torus (donut) like container that able to control massive heat. You gonna need to design toroidal field using electromagnetic to contain the magma. So something like copper or a high density magnetic metal that help keep the plasma contained. Plasma + magnetic fields= Power. Butt-loads of power. But if you want to add some more juice to it. You're gonna need some type of core which the reactor can feed off of. Well here my idea:
invent a smart metal which carries the same similar characteristic of vibrainium. Which in the marvel universe vibrainium absorbs vibrations and kinetic energy. That energy is stored within the bonds of molecules that make up the substance but the reactor vibrainium or smart metal will act a different way. It absorb vibrations (sounds) Which the reactor delivers vibrations to the reactor and the smart metal absorbs it and channels it into core power. Thus giving massive juice to the reactor since it is constantly absorbing and channeling into "Arc power" Leaving plenty of juice for thing like flight. Ok so this took a little more research but i think i figured this one out. Ok so as we can see, Tony doesn't used any onboard fuel or liquid hydrogen or oxygen instead he used them in the gas for. The movie site said that he perfected his boot based propellants to include micro repulsors turbines. As some of us know micro-turbines uses hydrogen as a fuel. So Stark micro-turbines act the same maybe more powerfully but anyway, Tony jet boots used propellant.. Propellant is the general name for chemical used to created thrust. Knowing tony stark he used clean fuel source so he would most likely use hydrogen gas which is 2 hydrogen atoms put together which combust violently with oxygen and can create thrust. As a fact since hydrogen burns clean at full thrust the flame becomes nearly invisible. His jet boots could use air intakes which can conclude oxygen from the air and hydrogen from water vapor in the air. Go through a repulsors combustion chamber and boom!!! He can fly even at high super sonic speeds, due to high build up of hydrogen gas which is constantly being combusted to provide thrust but the build up is safely contained in a compressed sealed are in the boots which protect from any "accidents" Due to hydrogen gas being highly flammable but with the right mind it easy for it to stay contained. But high amount of the gas can be released and give stark an extra boost. So i think the suit is possible and can be created. Just have to have that right motivation.