The 220 volt circuit for the dryer was cabled with 3 wires with no ground. Pulling a new 3-wire plus ground cable through the house would have been very difficult. I ended up running a ground wire to the copper plumbing for the washer and verifying that it gave a good ground. I talked to my cousin who is a licensed Master Electrician and he said that was OK.
For an isolated fixture here and there I think you can have a separate ground, but I would think it would be frowned upon if you did that for all fixtures in the house.

Also - what type of cable is it? If it's knot and tube, you need to replace that stuff anyway. If it is armored cable (BX) the steel sheath can act as the ground and you can ground a 3-prong outlet to the box after verifying that you have continuity of ground through the sheath back to the ground at the service panel. Using the steel sheath as the ground was common back in the day, but would probably be frowned upon for new work these days.