friendly_title() for pure non7-bit languages

Preface:

It's old, ancient problem in all Elgg version, not solved even now. Dear developers, please remember - there are 8bit (and "more-bits") alphabets in the world, current friendly_title() can operate so-so only with Latin-1 without producing nignmare

Face:

I'll get (probably, soon) extended (UT8-aware) version of friendly_title(). My question is - how I can correctly overload elgg's core function in custom module (I don't want to use "hackish way")?