According to the Wayback-Machine there have been only the four MS Windows 2000 versions you listed.
See the following link for reference: http://web.archive.org/web/20000815061513/http://www.microsoft.com/windows2000/guide/platform/overview/default.asp
The snapshot is from the 29th of February 2000, about 14 days after the MS Windows 2000 release. This http://web.archive.org/web/20011201220210/http://www.microsoft.com/windows2000/default.asp snapshot is from the 1st of December, about 5 weeks after the release of MS Windows XP.
I guess that settles it ;)