How To Build Flexible Web Forms

I'm using asp.net and I need to build an application where we can easily create forms without recreating the database, and preferably without changing the create/read/update/delete queries. The goal is to allow customers to create their own forms with dropdowns, textboxes, checkboxes, even many-to-one relationship to another simple form (that's stretching it). The user does not have to be able to create the forms themselves, but I don't want to be adding tables, fields, queries, web page, etc. each time a new form is requested/modified.

1) How do I structure a flexible database to do this (in SQL Server)? I can think of two ways: a) Create a table for each datatype (int, varchar(x), smalldatetime, bit, etc). This would be very difficult to create the adequate queries. b) Create the form table with lots of extra fields and various datatypes in case the user needs 5 integers or 5 date fields. This seems the easiest, but is probably pretty inefficient use of space.

2) How do I build the forms? I thought about creating an xml sheet that had the validations, data type, control to display, etc. as a list. Then I would parse through the xml to build the form on the fly. Probably using css to do the layout (that would have to be manual, which is ok). Is there a better/best way? Is there something out there that I could look at to get ideas?