Well, I don't about "sufficient interest," but I certainly do see the need. I was very surprised not to find _any_ such system online. What I have in mind is a modular system with multiple profiles feature.
For example, lets say, user johndoe has a create one such account @
www.LQ/sysprofiles/johndoe. His account contains N machines, and each machine has its own confguration (modules). Now he creates different profiles, (say, game, devel, ...) by providing only selected modules from selected machines, so that he can use
www.LQ/sysprofiles/johndoe/game or
www.LQ/sysprofiels/johndoe/devel as the relevant links.
The simplest analogy for this would be the "collections" feature of addons.mozilla.org.