Comment 9 for bug 135921

How to mess up your file system depends also somewhat on how your locales are set up etc. I would perhaps suggest you use something like Perl, where you can unambiguously and portably express stuff like

vnix$ perl -e 'rename("Random.mp3", "R\xe4ndom.mp3") || die "Could not rename: $!\n"'

This still depends on the underlying file system and what not, but works for me on ext3 on Ubuntu Linux. (If you ls this file it will show as "R?ndom" and tab completion in Bash will produce a Unicode "unknown/invalid" glyph -- Nautilus does that in spades, adding an (invalid encoding) after the file name --, but raw access to the file system etc will show you that the file name is exactly as you requested it, with a Latin-1 ä, as in "Rändom.mp3", only of course here in Launchpad it is in Unicode.)

More generally, you can use iconv to force silly round-trip conversion errors:

vnix$ echo rändom | iconv -f latin1 -t utf8
rändom

(... assuming your shell correctly allows you to enter a proper ä and that your locale is set up to use UTF8.)

I'm not saying I know at all how to solve this, but any developer should be able to reproduce, trivially.