I just found this Mambo 4.5.2 to Joomla (latest) online migration tool. For MONTHS i have been looking into this migration, because i have several websites on Mambo, and wanted to migrate them to Joomla. At this very moment i am making a back-up of a "guiney-pic" website to test theis conversion at. It worked for so mnay people, it seems, thus it's still in Beta. Here is the support thread, at Joomla forums. Will let you people know in an hour or so, how it ended up. Hope it helps other people.