Front end data collection - backend document production

I would like to hear how you would build a site to collect basic data from visitors/clients which would then be used to generate filled in forms. The visitors and clients will be entering data from among the 50 states and each state will require some of the same basic information and then specific information - ideally every client will have to fill in inclusive information and the form in which it will be entered into will only pull in what it needs. I do not care how you accomplish this task - the front end exposed to the client must be attractive and easy to use, ideally data driven with only a few sections to be answered at any one time. It will need to provide membership provisioning so the client can log in and out and continue entering information where they left off. The form in which the information will be integrated into will be provided once the front end is finished. Along with the front end data entry, I will need a company website which provides the purpose of the company along with faqs, tos, legal and other information commonly associated with the typical service website. More details will be provided upon receipt of your bids and interviews.