Under their new business model, instead of making money by selling the OS, they will now make money by selling apps. Without a MS account, the store won't work. With the VL versions they still will be making money off the OS itself.
When I have multiple drivers with the same ID I let Windows determine which is the best driver to install. I don't touch the INF's in order not to invalidate the WHQL certificates.
I think some of your procedures are overcomplicated, here are some of the thing I do to solve the same problems. On my network I created an AD account that can join a computer to the domain but can't do much else. I don't care what model I'm installing to because I have INF files for every device in my organization (some of them were extremely difficult to extract from packaged installers). For user profiles I use roaming profiles. I set the policy for WSUS from cmdlines.txt.
The easiest method is to install Windows on a simular motherboard and to transfer the HD to the powervault when finished. as long as the motherboard uses the same HAL and mass storage driver you should be OK, all of the devices on the PowerVault 715N have their drivers build in to 2003 (I never tried XP). If you want to do it the hard way take a look at http://en.community.dell.com/forums/p/17729873/17889070.aspx.
It would also help to modify the Installation Sources value in HKLM\SOFTWARE\Microsft\Windows\CurrentVersion\Setup. That way you won't have to tell Windows where the files are every time you need them.
What is running is called "Mini-Setup". Windows has already been completely installed and it is only showing enough of the screens from setup to personalize the PC.
You will need use the System Builder Bypass Tool. If you are registered as a System Builder you can get the tool and more information at http://oem.microsoft.com/script/contentpag...x?pageid=561187.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update] "ScheduledInstallTime"=dword:00000012
The sets are interchangable between x86 and x64. A generic x64 key can be found in the MS article titled "Preserving OEM Pre-Activation when Re-installing Windows XP"