Dragging back to my knowledge of property law, land rights as commonly understood in the UK today started in 1066, during the Normandy conquest of England. The monarch declared sovereignty (and thus ownership) over the area. The land was then vested to the conquering lords and barons, as a way of maintaining favour and being able to control a large population with relatively few people. (This effectively is how a feudalistic system comes into place. The land is 'owned' by the fief, and then creates a reciprocal relationship of goods/services/labor/military services in exchange for the use of the land.)
Later on, when parliament became more powerful, the land taxes would become very extravagant, and thus you would get tricky vesting of titles, the splitting of the legal and equitable estates, and many bankrupt freeholders looking sell their properties, all of which lead to the dispersement of land ownership to peoples other then the landed gentry (landed gentry - get it?)
As for simply settling down on a bit of land which apparently no body owns, take a look at some of the
adverse possession laws. The logic behind them is very similar to what the OP was commenting on.
As for Australian native title, just a couple of comments. Just about all jurisdictions in Oz hold that native title is unalienable (ie that it cannot be sold, transferred, swapped, or disposed), except for the government. While I'm not saying that you should go out and read Mabo no 2, just a little bit of wikipediaing will give you the gist. Basically, native land rights in Australia were not extinguished with the assumption of colonial sovereignty, provided that they could show a continuous and exclusive occupation of the land. I'm not going to go into why this is/is not a good doctrine, but it is one which stands. 'Whiteman' does NOT try to lease it back to the original owners! You might also be interested to know that Australian Aboriginals didn't even have a concept of individual land ownership until European occupation, which is why you can have entire tribes having joint ownership over an area of land.
You might also be interested to know that in the UK, the only group which supports the redistribution of the land are the Greens...