Layered multilingual website
Back in my prepress days we were using Kodak Prinergy which has a wonderfull feature for making layered versioning. It analyzes layered pdf's for creating plates for language shifts during printrun.
Such a feature would be nice in Muse, to make multilingual websites using layers in muse.
A common layer to all the elements common for all language versions, and a language layer for each language you want on your website.
After defining a common layer and the language layers, Muse generates the complete site.