I have to agree with the others. Though I would love to get my $500 back, I can't imagine it is worth fighting for. Plus, I am not sure where a crime was committed by Mundus. The SEC authorized the number of shares, they released them to the public with no promise of any return.
Though I don't like the practice of companies using shares to pay their bills, and raise cash to support them, it is a common, and legal practice which is utilized everyday by small startup companies. Yes, Mundus did put out a few PR's to try to keep their name in the public. If you read them, they all say things like they were investigating or interested in using their technology for new practices. The use of UAV helicopters is a growing phenomenon, and is still pretty much in it's infancy. I think Mundus has just as good of a shot as anyone else to succeed in this arena.
Unless you can somehow prove that they are a shell company, and there is in fact no inventory and no product, I am not sure what basis you would have for a suite.
The only "crime" I see at this point would be unethical practice of the market makers. Though I realize they are supposedly a necessary and valuable part of the market. When they purchase millions of the shares, and then sit on the ASK, and pushing down the BID, it allows them to short the stocks and be the only ones making money.
I would be shocked if you can get enough people together to actually make a "class". That being said, if you can in fact make a case, and even win it, more power to you. Though I don't agree with frivolous lawsuits, in fact, I think that is the biggest problem with the American Legal System. However, if there is any evidence of wrongdoing on their part, then a lawsuit would be the correct course of action.