I am looking for a floor flange for 1/2 inch pipe with a 5-6 inch diameter flange at the floor.

Cableto - I not sure you can buy one like that , check with a reg plumbing supply store, if they don't have one ask them if they can order one for you, IF no luck go to a machine shop and have them make you one . GOOD LUCK & GOD BLESS> ;:: IF I have helped rate my answeer below. :::: F.B.E.

Purchase a floor flange for larger size pipe and reduce down to 1/2" using a series of bushings.