FWIW I have made a first stab at a DokuWiki dialect for the Perl module HTML::WikiConverter
The module is posted at http://www.citlink.net/~messengertj
as DokuWiki.pm. When defining a new WikiConverter object, dialect must be specified as 'DokuWiki'. test.pl is a Perl script to convert an HTML file (argument) to DokuWiki. WikiConverter works hard at stripping leading and trailing blanks. Unfortunately, that zaps some DokuWiki mark-up. I have used ` as a placeholder for blank and there is a post-processing step to replace those (s/`/ /g). Anyone interested is welcome to these. (At present test.pl also makes a MediaWiki conversion. The base_url is the second argument.)
HTML::WikiConverter is available from CPAN.