I know someone mentioned writing a script to fix imported vB quote tags to work in xenForo. Has anyone done this yet?
Not really. There is xf_import_log table that stores IDs map (until new import is initiated). So you need to only go through all the posts and replace old IDs with new ones without needing to do something with vBulletin database anymore.The mapping of all the quoted vB posts id's to the new post ID's generated by the importer, would require a second pass of the importer, and quite server intensive for large boards I would gather .