I'd recommend that you take a look at two things...
One of the best business frameworks, in my opinion, is the Component Scaled Logical Architecture (known as CSLA). It is so easy to use, yet provides the advanced functionality you will need as your applications grow. You can find more about it here:
http://www.lhotka.net/
The other thing you should look into is CodeSmith. This tool lets you create or use community-created (templates for CSLA already exist) templates and then use these to generate your classes. Basically you create your database first, and then it will use the fields in your database to create your classes. You can find out more about it here:
http://www.codesmithtools.com/
I hope this helps...