Rhino translator reads and writes .3DM files and works with the Mac and PC versions of the modo 301 software.

Will it read Moi 3DM files? That could be the best combo, Moi for nerbs Modo for the rest, SDS etc.
http://www.luxology.com/whatismodo/plugins/plugin_rhino_translator.aspx

and more

Luxology Licenses Pixar Animation Studios' Subdivision Surface Patents
http://www.luxology.com/press/release/100807_pixar.aspx