@herbalist Unfortunately, the great size of SP4 can be a disadvantage. Howewer, I'll try to help anyone willing to remove some of its components by publishing the source files used to build the SP4 (except for the certificate used to digitally sign all updated files).
You can modify the update.inf and the other information files, so that they contain only the necessary files for your needs. I have left my comments in the INF files intact (except for the layout/txtsetup/dosnet ones) specifically for that purpose- to help you customizing these files.
There is no perfect solution for any problem. I have tried to make SP4 fully customizable but, on the other hand, only advanced users will have the skills to complete the task.
Have you checked with the guy who compiled the unofficial Windows 2000 update? I remember he'd mentioned that the installer was trunkating some long registry entries.