The NanoRex "MMP" file format has been implemented for Open Babel:
http://www.nanoengineer-1.net/mediawiki/index.php?title=Import/Export_Different_Chemistry_File_Formats
At the moment, this file format appears to be in flux, along with the program itself. Eventually, this should be revisited and brought into the main Open Babel tree for maintenance.
-Geoff
