You can use glmodel: http://www.noeska.com/dogl/glModel.aspx
it can even load .3ds from memorystreams :-) Even when loading a .3ds from file a stream is used and when modifying the mesh it is only changed in memory.
Only the saving of a .3ds file is a work in progres. But you can save to milkshape ascii and obj even when the file is loaded as an .3ds .