TBK you are asking a lot from one gun. I doubt that you will find all of your requirments in one of the shelf gun. Do a search for drillings on gunshop.com and gunsamerica.com and some of the dealers that advertise on this site. I've never seen screw in chokes in a drilling. Most older ones are choked full and full. 12ga and 30-06 run premium for price. I've also never seen 20-22inch barrels. You could get one made with your requirements but I doubt that you will find a used one with them.