Anything is possible, especially in the presence of bugs or various typing-utilities/spelling-checkers/etc. Blind typing into the bitcoin-qt window is a classic failure mode for that, e.g. for Germans:
Kongressstraße vs. Kongreßstraße.
For KGB agents the example would be: Microsoft vs. Microsoft. (For non-KGB-agents: the second "c" is actually a cyrillic "s".)
Edit: Oh, and guys, please don't race into registering the homo-glyph accounts for the Bitcoin luminaries. Registering as "Gavin-non-break-space-Andresen" is not that funny.
Edit2: Fixed the external link.
After all this trouble with the encoding on linux I switched back to Windows 7 to try to crack my password. Cracking a test-wallet with a password that contains an umlaut now works with Revalins' script.
However, the next issue is up: the ruby script is so slow on Windows (compared to Linux). On my linux laptop with a Core i7 it tried passwords at a frquency of about 10-20 attempts per second. On a Windows 7 machine wiht a Core i3 it slows down to something like one password per second. Part of this is probably due to the CPU used, but the larger part seems to be OS specific. Is there anything one could do about that?
Desperate,
Niklas