I have done some number crunching doing the same thing. Unless you are retired and live next door to a marina that you want to carry the items, there is no profit in making them.
By the time you buy a hook (.25 for a 7/0 @ wal mart), (6' Ande 80# line .20), an information card (.5) and a small zip lok bag (.3), you will have $0.53 of material in each leader. You might get $1 wholesale, the retail probably would be around $1.50. Not much room for profit.