i think this satisfies your requirement. It's documented on [[mw:Extension:Universal_Language_Selector#Alternate_ways_to_load_fonts]]:

Alternate ways to load fonts, By specifying font-family

Inside the wiki text <span style="font-family:'YourFontName';">YourText</span>, webfonts extension will check whether the font is available with the extension, if so it will download it to the client.

There are some advantages the classes have:

• They are more descriptive. <span class="script-buginese">some text</span> is more obvious than <span style="font-family: Saweri, sans-serif;">some text</span>. You had to look up the exact font names in the documentation, while you could use classes without doing so (if you know the English name of the script).
• They are shorter.
• Classes can be used in advance, even if there is currently no font for the script. Then it will work once a font is added to ULS.
• Users can override the fonts in their common.css if they have a font installed for a script they like better.

Isn't the wiki way to write a template ala {{script-buginese|Text goes here}}? That way the communities themselves can also decide which font they want to use without us dictating it.

In my opinion adding such classes to ULS would entail quite a maintenance burden.

(In reply to comment #3)

In my opinion adding such classes to ULS would entail quite a maintenance
burden.

Somebody has to maintain the classes/templates/whatever, to keep them up to date with the fonts provided by ULS. I don't see a reason why this maintenance should be done by the single wiki communities. When you add, change or remove a font from ULS, you have to update the central config files and automatically re-build the others anyway, so why shouldn't there be a file with CSS definitions like above which is updated along with these files?