I certainly do not agree with your reasons for getting one, and do not see how anyone except neo-nazis or white supremacists would see it as fun.
That being said, I don't think you looked very hard, an image search on Google pulled up three theatrical costume stores that have the full attire.
I know your views on the matter won't change, but do keep in mind that wearing such an outfit in public is quite distasteful, rude, and ignorant. For your own sake, be careful who you wear that around.
Funny, California Governor Arnold Schwarzenegger often wears full Nazi garb to costume parties and give gifts of Nazi collectables to his friends, colleges and visiting political leaders.