I would like to build a comprehensive list here. Off the top of my head there is:
 
Control panel => Supported OS\'s
============================
 
Cpanel - cAos (2, 2 64-bit), FreeBSD (4.2, 4.3, 4.4, 4.5, 4.6, 4.8, 4.10, 5.0, 5.3, 5.4, 5.3 64-bit, 5.4 64-bit), Mandriva (7.2, 8.0, 8.1, 8.2, 9.0, 9.1, 9.2), Fedora (1, 2, 3, 4, 3 64-bit, 4 64-bit), RedHat Enterprise Linux (2.1, 3, 4), SuSE 9.0, CentOS (3.x, 4.x, 3.4+ 64bit, 4.x 64bit), RedHat Linux (Fedora-Legacy) (7.3, 9), Whitebox Enterprise 3, Debian (3.0) (BETA), Trustix ES (2.0, 2.2)
 
Plesk - Red Hat® Linux (7.3, or 9.0 i586), Red Hat® Enterprise Linux (2.1, 3.0, 4.0), FreeBSD® (4.9 or 5.3), SuSE® Linux (9.1, 9.3, 9.3 64bit), Fedora (Core 1, 2, 3), CentOS 3.3, Debian 3.1, Ubuntu 5.04
NOTE: SWsoft will also discontinue the following Operating Systems on December 31st, 2005: Red Hat 7.3, Red Hat 9.0, Red Hat Enterprise Linux 2.1, Fedora Core 1, Mandrake 9, and Mandrake 10. As of this date, SWsoft will no longer be able to support, patch, troubleshoot, or answer support issues related to these Operating Systems.
 
DirectAdmin - Redhat Linux (7.2, 7.3, 8.0, 9.0), RedHat Fedora (1.0, 2.0, 3.0, 4.0), RedHat Enterprise, CentOS (3.x, 4.x (64-bit is supported in 4.x only)), FreeBSD (4.7, 4.8, 4.9, 4.10, 4.11, 5.0, 5.1, 5.2, 5.2.1, 5.3, 5.4), Debian Sarge/Woody
 
Ensim - Fedora Linux (Core 2) or Red Hat Enterprise Linux (ES 03)
 
Webmin - SuSE Linux, United Linux, Corel Linux, TurboLinux, Cobalt Linux, Mandrake, Linux Corporate Server, pclinuxos Linux, Mandrake Linux, Conectiva Linux, ThizLinux, Desktop, ThizServer, MSC Linux, SCI Linux, LinuxPPC, Trustix SE, Trustix, Tawie Server Linux, TinySofa Linux, Cendio LBS Linux, Ute Linux, Lanthan Linux, Yellow Dog Linux, Corvus Latinux, Immunix Linux, Gentoo Linux, Secure Linux, OpenNA Linux, SoL Linux, Coherent Technology Linux, Playstation Linux, StartCom Linux, Yoper Linux, Caixa Magica, FreeBSD, DragonFly BSD, OpenBSD, NetBSD, BSDI, HP/UX, SGI Irix, DEC/Compaq OSF/1, IBM AIX, SCO UnixWare, SCO OpenServer, Mac OS X, Darwin,
OpenDarwin, Cygwin, Sun Java Desktop System, Generic Linux, Windows
 
H-sphere - RedHat, RHEL, CentOS, FreeBSD, Trustix, Whitebox
 
 
Can you think of any others?

I was reading a blog at neteverything.blogspot.com and it told about Iron-admin, I checked it out and it\'s pretty advanced. The blog covers a lot of  issues for Linux & Multi-platform integrated control panels.