After months of speculations, if there could be a Longhorn Server Edition, we know the truth. Read more...
Internal Microsoft sources told us today that such a version is under developement. But it won't be a great thing. It will be just a minor update to Windows 2003 Server. Blackcomb will be the next complete new server OS. This minor update will contain the new SQL-based filesystem "WINFS" that should be really faster then the old NTFS and FAT32. Source: Wininformant.com