Eric,
I would still note down your supervisor as your contact person. This is because your supervisor can be the contact person for multiple projects, making a review much easier on you, than having to write to several customers and get their input. You yourself can never be the contact person.
Also... PMI does not penalize you for the fact that you work for a small company. After all... there are probably more PMs working in small and very small companies in total than there are working in large ones. So PMI is aware of this and knows how to handle it.