I might suggest that if you're using WinPE to deploy Windows 7, you use DISM to deploy the image and inject drivers into the image while in Windows PE. That's how I'm doing it with a custom AutoIT script - it deploys a WIM image, and detects / installs the correct drivers based on model. You just need to select 3 things in the script - WIM image, Target, and base location of the drivers. It's a very similar method that Microsoft's SCCM would deploy Win 7.