Neither of the "fuzzy" search algorithms is good for
French names. Daitch-Mokotoff finds Gravelle as a
match for Groleau. Neither that nor Soundex/Miracode
matches Groleau to its variants: Grosleau, Groleaux,
Groslot, Grolot. All of these are pronounced the same
and were used interchangeably.
A French Canadian fellow has invented an algorithm
which he claims works pretty well for French surnames.
If there's any chance of making it another option,
I can contact him and ask whether he's willing to
share it.
There's also one called Metaphone. I don't know
anything about it.
Finally, what about an option that would use a
cross-reference table of known variants that would
be created by the admin and/or users of each PGV site?
Such a table could tell the engine that
Waack = Waak = Waage but NOT tell it that
Waack = Weiss (which is a Soundex false positive).