I have heard of a Fruiting mangosteen near me in the redlands. Belongs to some crazy, secretive, hippyish, colombian or cuban (i forget) guy who is super into organic and farming.
I haven't had a chance to verify it is a mangosteen and not some other type of Garcinia, My mother is his friend and has seen the tree, but she can't tell and ficus from a longan.
I'm hoping to join this exclusive club. I already have the tree and the spot picked out. Now I just have to rent the back how and buy the soil.