A good way to start is to read and view these Documents:
Best Known Method for Deploying Windows 7
I am also pretty sure, that you can't deploy while the user is working on the System.
The only thing you can do, is giving him a replacement (for example WBT/Terminal Client) while deploying/provisioning.
Make also sure, to include Service Pack 1, so you don't need to upgrade again after a short period.
We also included other languages in our Installation and packaged our Office Install in a ZIP File.
The Deployment went smoothly and without bigger problems, but our Rollout went step by step with
5-10 clients per Day.
One thing to bear in mind when looking at this kind of migration is how rapidly the customer desires the migration to happen and what level of user impact is acceptable.
There are a number of ways you could theoretically achieve this migration, some just using the 'official' methods, other using a more 'hybrid' method.
The official methods may be fine but it depends on what you have available for image storage, and critical timeline information. I'd say start defining the parameters of the project and then examine the options available since the 'best method' for you may be completely different to the way LANDesk was designed; I know it has been for me in a number of instances and some will comprise multiple steps to prepare systems prior to migration.
The One-Stop Shop for LANDesk Enhancements