Quote: "Reversing the polarities would increase their chances of getting hit by a missile launched by the enemy."
This is the risk you take to look awesomely cool
Imagine a tank driving through a city and everyone's guns (and random metal stuff) flying off and sticking to it. "Yoink, yoink, yoink, I'll have that thank you"
Quote: "Could you use it to fire things? Like say, a guy in a suit of metal armour. Because this could be a cheap means of transport."
and then have another electro magnet that slows you down at the other end.
that would be pretty darn cool.
I was thinking about a personal force-field. You could have a really thin metallic suit and be completely impervious to gunfire, even RPGs!
I'm not sure if you could fit the superconductors onto your suit with current technology.
[edit]
now I think about it don't the Japanese hi-speed trains use electro-magnets to propel them along the track?