Its not the money that is the issue. Its the fact that you can actually do it. That is the question, and we are asking you to be realistic. Can you actually do it? Because you are here asking about USB host/slave interface and then you say you have to get a chip made custom. I really hope you know what goes into making a microchip. It isn't simple, and its nothing like ordering a custom circuit board. To be asking such trivial questions such as the USB thing would scare any investor.
So I'm not answering your original question; I just want to make sure that you aren't getting too hyped up about something that may be over your head. If you can't do it all by yourself, its best to get a team of people who can help you out. A team of people you trust. Its easy to keep everything to yourself and try and learn how to get all the knowledge so you can do it on your own. It is difficult to let somebody else in on your idea and let them do their thing with your baby. I just want to make sure you aren't going about this the wrong way.