SME server isn't really suitable for hosting in a data centre. It's designed primarily to support a LAN with local users. Such a LAN usually doesn't exist in a data centre.
You can fudge it, but I'd say there are other more suitable distros for running a hosted website.
What would your recommendations be?
If the hardware has 2 nics to configure as SERVER/GATEWAY and the admins connect to the lan side in a secure manner, what to lose? The admins still gain the advantage that config can only be done "locally." And they gain the reliability of the templates.
If not SME, this pretty much leaves choices to:
-a REDHAT based release (CENTOS, FEDORA)
-a DEBIAN based release (DEBIAN, UBUNTU)
-or FreeBSD.
With a control panel of:
-cPanel+Fantastico
-Interworx w/NodeWorx/SiteWorx
-Plesk
-Webmin