With all due respect, but that Xandros page I'd like to dismiss it as marketoid speak.
Maybe have a look at SME Server (formerly E-smith). Here's their "design philosophy":
http://contribs.org/modules/phpwiki/...n%20philosophy
While LQ is more or less a technical set of fora I would like to digress for a second and say that IMHO providing a GUI-based solution for "negative" reasons like lack of Linux knowledge or general administration skills will, if not supported by a good support contract, not be successful by definition. I think you could help them (and yourself) by defining area's the admin can work in he/she is familiar with and tack on a small well-paced (self-)training scheme to work on other area's. This will keep "fear" levels low (we all know what anger leads to) and gradually expand knowledge until a GUI is only needed for "positive" reasons like speeding up tasks. Just my two cents though.