We (at @glowingblue) are also thinking about this issue of multi-language support for elements where the label (string) is set in the admin interface.
We haven't got a solution yet, but I kind of like the idea of sijad :
in settings table we can save a key instead of the real values.
We could add a UI that helps the admin to create keys, he can then set the values for in FoF/Linguist.
We have a customer that needs this feature for the end of the year. If I get time to do it, maybe we will release this as a premium extension on @Extiverse.
(cc @MrB)