I don't know if it's in this thread or not, but as I've posted before this is NOT the ultimate use of the technique. It's really intended to be used in maps where the nodes can be placed as needed rather then on a grid. I used the grid as simply a way to show people how it would work.

Also, you are assuming every node must always be connected to every other node. You can use varying levels of grids to get the same effect at much less memory usage. Or, even better, use different searching techniques as needed. For instance, use a fine-detail A* algo to find your way to the door of a room and use this to find your way from room to room. Make sense?