Generating the business objects from the DB is always a very tedious tasks and the solutions available always pose a number of limitations. I’ve started exploring PLINQO that looks like a very powerful and customizable solution, based on CodeSmith templates, that builds and improves on LINQ to SQL.
PLINQO is free but you need to have CodeSmith Professional installed on your machine to use it.

You can learn more about PLINQ at http://plinqo.com

The code generation can be embedded into the build, although it doesn’t make much sense to me to regenerate all the classes every time you compile.