Using the CodeGen_MySQL_Plugin i have now been able to create my first working fulltext plugin: gzip_fulltext
gzip_fulltext will uncompress data that was compressed with MySQLs COMPRESS() function on the fly before passing it on to the default fulltext parser. Data that is not gzip compressed will be passed on 'as is'.
Update: there were some minor compile problems with yesterdays release, these have been corrected and th download link below fixed