All of 3.x’s map files are proprietary so theoretically yes a tool could be written to convert them. In practice this would be a lot of work because for example there would need to be a new version of every object with identical dimensions/transforms. At least in the beginning I think my time would be best spent moving forward with new fresh content rather than remastering older content. I remember saying something similar during 2.x -> 3.0 and we got PEI so you never know!