I don't think the spacebar stamp feature works across files though. I haven't tried it, but I'm pretty sure it only works in the same file where the object is selected.
You can always copy something out of one file and paste it into another file.
Hhmm, I guess I'm assuming "new workspace" means another file. But maybe not. Well, I'll post anyway, just in case.
If you're looking for a stamping feature, besides the one Moini mentioned, the Spray tool sort of works like a stamp, if you configure it the right way on the control bar.