I really don't think that exporting to a MAX scene file would be of much help (at least without Max that is). Currently there is the script from Mirabar, but that requires Max to run - it is not a stand alone utility.

Deep Exploration might work - though for that you would need an export/conversion utility to change it from MAX or XSI files to WED (wmp, wmb, or map). There might be one for MAP files, but I doubt it has ones for the native formats. Another option is pursuing a plugin of your own. If you can get enough users together, you could possibly get a programmer to write an export plugin for XSI like the one for Lightwave and Max.