You should be able to export directly from Maya as .3ds files, if I remember correctly. I'm using 3d Studio Max, though.
Have you tried FILE -> EXPORT ----> 3ds?
Rather than saving the file? When I used Maya it could export to 3ds format, but perhaps the company I worked for had a plugin. Otherwise you can get for instance Milkshape 3d, which is a shareware low-poly modeller, and convert .OBJ files into .3DS. I don't know if Milkshape handles .X though.
Or you could splash out a couple of hundred and buy 3d Studio Max which can read Maya .OBJ files with a free plugin and use the free plugin PANDA to export .X files as well.