Hello. Please dont misunderstand me. But it seems you are here to exploit people. Who in this world will build you a game engine of that circumference for you $3000. And that also you will pay by paypal or bank transfer, and you know why you want it to be done by paypal or bank transfer. You are intelligent :) . If you really want to get that project done, i would give you a friendly advice, hire someone in your local itself.