I have just slipstream SP1 into all Vista versions (ULTIMATE, HOME BUSINESS, etc....)
keep all components, no changes, just add SP1 x64.
take about 7 hours, When it was finish, I Rebuild Vista folder with "LOG", because If I don't Rebuild ISO was to big to write it.
Lol, so say 1hr per version or something? I would never get any version of windows finished in time at that speed.
Here it takes about 5 to 10 minutes. Ramdisk forever..