Hi guys,

I'm aware of at least two areas which will respawn with friendly units after being cleared:

Primm - Vicky and Vance. Once a new sheriff has been found wait 3 days and a group of NCR deserters will appear inside the casino. Kill them or scare them off, wait another 3 days and the casino will re-open for business.

Prospectors Den - Clear out the Jackal gang and about three days later two NCR prospectors and a merchant will appear (Pretty cool, just discovered this one!).

Are there any other locations which will respawn with friendly units once they have been cleared?