To get this suit all you have to do is blow up Megaton (you will get a lot of bad karma for doing this).

To do that you go into the saloon in Megaton and go to Mr. Burke, he will instantly talk to you.

Agree to help him blow up Megaton then go rig the bomb.

If you don't have enough skill go take some mentats then do it.

Go to Tenpenny tower and go talk to Mr. Burke and blow up the town. Then you will then get the suit.