There is extremely slim to no chance that this is legit. At around this time last year, lots of people got screwed trying to buy XBOX 360's from Chinese dealers in the same manner that you're trying to buy your PS3s. They organized group buys, went through middlemen, went directly to the "dealers," but ultimately ALL of them got conned. It doesn't matter what the quantity was; 10, 100, 1000, 10,000, all of them got screwed. People who bought 1,000 and then took orders from other people screwed both themselves and their customers.
Think about what happens when you wire the money to these guys and they don't deliver. You have NO recourse. The Chinese government will not care about your case. The US government has no jurisdiction. You can't take them to collections like a regular business because they weren't a business to begin with. When you try to find them, they will have disappeared.
The only possible ways for this to even remotely work is:
1. You pay by credit card and can do a chargeback. Very very unlikely that they will take credit cards. Dealers, both legit and scammers, just don't do it. In the world of business much of the ordering is done on account anyway.
2. They use COD and you get to inspect the products *yourself* when the items are delivered, and then you release payment. You will pretty much have to inspect all 1000.
3. Fly and buy. You fly over there, inspect the units, and fly them back yourself. You will pretty much have to inspect all 1000.
Since there's no chance that anyone has PS3's, all above points are pretty much moot. They might tell you that they'll use a third party nationally renowned inspection agency like Hellman's and tell you so wire the payment to Hellman's. This is a fake Hellman's account. They may send you a photo of a sign with your name on it next to a mound of PS3 boxes. This is fake. They may go through *legit* dealers, and when you buy from those dealers but they never get supplied you better hope that those legit dealers are honorable enough to refund your money, because if they do they will be footing the bill themselves.
Just put your $500,000 into an interest bearing account and be done with it.