Well, let’s see here. I just got into work this morning, and I’m not quite with it yet (need another mountain dew). I don’t know if I completely understand your question, but let’s try this:
Within the “Save As…” dialog, make sure that “Show Export Dialog” is checked. Now, after you pick a name for your file, the Export Dialog appears. If you notice, at the bottom, there is a group of radio buttons titled “Rescale”. Using these radio buttons you can adjust various aspects of how large the model is (in the identity matrix).
On a side note, you could just pushmatrix and scale the scene if it isn’t large enough.
Well, nonetheless, check out that dialog. The default size = 1.0 and origin = 0, 0, 0 will usually be sufficient, however, providing you scale the object. <shrug>
Hope that helps. /me yawns and hits the soda machine again.