Do an advanced search for "overhead roof console" at least one of the threads links to home made consoles, if they don't show enough about mounting do an advanced search for "installing factory roof racks" that shows how to pull the roof lining down and you can see for yourself where you can mount things.
There is several spots but you will have to be careful of the weight hanging off each point, the B pillar roof bar would be the strongest and depending on materials used as to how much I would trust other roof bars especially if you bounce around the bush a bit.
