Equip box only goes to 70. You can get the dual bowgun from the legends shop. Boom, done.
For those who will start after the events are over, they can do the entire Mercedes quest line, to get the dual bowguns anyway. They go all the way up to 90, with the lvl 90 one being name tagged. All tradeable.
Captains in the captain minidungeon drop the reverse dual bowgun recipe, so eventually those hackers who farm chaos scrolls and mystery books from those will start pulling out the recipes along with that at a cheap price.
http://img689.imageshack.us/img689/4647/facedf.jpg Best reaction shot ever.