And maybe to add FreeBSD 7 support (including 64 bit version) ?
FreeBSD 7 will be supported in Plesk 9.
ftp://download1.swsoft.com/Plesk/Plesk9.0/Doc/plesk9.0_whatsnew.htm
2.2. Software Requirements
Parallels Plesk Panel 9.0.0 for Unix requires one of the following OS installed on your computer:
* FreeBSD 6.1 (version 6.1-p10 or higher)
* FreeBSD 6.2
* FreeBSD 6.3
FreeBSD 7 will be supported in Plesk 9.
ftp://download1.swsoft.com/Plesk/Plesk9.0/Doc/plesk9.0_whatsnew.htm