I have developed a script that outputs rough rules.xml and disambiguation.xml files (which need manual modifications) from the data within An Gramadoir. I'm considering putting this up on Github, but I have concerns over licensing.
Most of the rules in An Gramadoir are under the GPL, which is problematic with the LGPL, although the Irish data is also under the Perl "Artistic License". One interpretation of this could be that the XML files can be under the GPL, whereas LanguageTool is the interpreter for the purposes of the license.
Only Irish and French (already converted?) have a reasonable number of rules, although the rules may be of use for starting a currently unsupported language.