A skin being a zip or tar.gz file, it is always possible to extract the XML file, modify the skin name, rezip and change the extension to be .vlt. Even if it is less convenient than renaming the skin file, it allows the same things as what you described for Opera.
BTW, if you want to translate the name of the skin, why not translating several other parts of the skin as well? For example, the Text control allows to display some text, which should most of the time be translated. The skin author is free to use the strings (s)he wants and I don't see any way, technically speaking, to provide a translation for these strings, other than letting the user change them manually (which is already possible as explained above).
And I'm not talking about the strings that might be embedded in the images of the skin
