I did a seo plugin long time ago (search for tfseo on vbulletin.org). The 2.0 version complained with this problem quite well. By stripping the words out in some non english words you will lose completely the sense of the word (i mean some italian one, for example). Bad SEO than.
@ => at
à => a
å => a
Å => a
This must be done, by a plugin or better from the core of the platform.
@DEVS: i would personally put a look at the way IPB or VBSEO works around this.