[rb12345]

PHP could just use the approach NTFS uses on Windows and convert to upper case instead:

http://blogs.msdn.com/b/michkap/archive/2004/12/02/273619.as...

[Xylakant]

Which would not help in this case, since in turkish the upper-case representation of `i` is not `I` but a different symbol. So the class you're looking for would not exist.

[rb12345]

Oops - looks like you're actually right there. For some reason, I thought I'd read that i and ı were both mapped to I.