If one puts localized chars in wikilinks ikiwiki will escape it. This works right from a technical point of view, but the URLs will become ugly.
So I made a patch which unaccent chars: http://users.itk.ppke.hu/~cstamas/code/ikiwiki/unaccentpagetitlenames/ This is a one liner change, but requires a bit of reordering in the code.
cstamas