I thought it would be interesting to visually compare the flight range of stingless bees and honey bees. I used Google Earth and the relative published research to make a comparison based on the Northey Street City Farm in Brisbane, Australia.
To be clear I don't keep bees at Northey Street (I have done similar diagrams for my sites) but it is a place most Australians will know and they do have both kinds of bee there.
The comparison really shows why site selection is that much more important for stingless bees.
The green is the flight range of stingless bees while the yellow is that of honey bees. Honey bees will actually forage further than this but hive weight decreases when that is the only forage and so it can't be considered sustainable.
I only know what I have observed with regards to your questions. Yes all natural hive propagation (that I have observed) has been to relatively close locations. They don't swarm as such, they just slowly fill a new hive with resources before sending over a queen and some workers. Because of this it would usually be within the normal forage range. They will also take over another occupied hive by fighting/killing but again it would have to be in the normal foraging range. They are certainly interesting bees to work with
With regards to density I have seen natural densities up to 10/acre but I hypothesise that the limiting factor in nature is the number of suitable tree hollows. They certainly don't mind high density (except for the fighting in spring/summer).
Just to update this one. When I wrote that article it was commonly thought that the maximum forage range of the stingless bee species in my area was approximately 500m. I made the above images based on this information.
The scientists behind the linked article below have now (well its over a year old) found that these little bees will travel 720m :)