I'm not familiar with any existing DBD for Refman files. I don't actually know what a Refman file is although I see that they can be exported to XML.
can probably access the XML dumps as a database. If there is a published spec for Refman (I couldn't find one on a brief visit to the site), then it shouldn't be too hard to build a DBD for. If you find the spec, write to dbi-users@perl.org where I and others will be glad to help develop a DBD.