paper space to model space question

Assuming that your model has not been cropped by a floating viewport, you could make a block out of the paperspace entities, insert it into mspace, scale it the inverse of the scale factor of the viewport, turn off any layers that were frozen in the viewport, and now your should have something that will look like your paperspace version (positioning issues aside). HOWEVER it will not be the same size in units. If you need it to be the same size, you will have to scale the whole thing down by the scale factor of the viewport. This may, or may not be smart.

CHangeSPACE.........part of Express Tools.....the last free version, anyway. I think it was in the R14 Bonus Tools, too, but I can't say for sure.

Yes, 2000i (sorry for neglecting that.)
Do you mean objects partially outside of the viewport area, going from MS to PS? If so, the entire object comes through to PS.