Another trick we have done is to open a new mxd, and then copy and paste everything from the old/bloated mxd, to the new. Then save and close the new one without doing anything additional.
If that doesn't work, then I would check to see if there really is a different in the data layers you are including in the smaller vs. larger mxd's. Maybe they are similar, but not the same exactly?
Edit: by the way, you may want to Moving Content to a more appropriate location like maybe GIS or Mapping . right now it is in the SDK for Android group which will not have see as many users that may have solutions.