Hey Mikey, ShawnB has his 5 foot firestik on a flat mount in the center of the front of his bed. It has survived the last year of HIS driving so I think it would last a lifetime of yours.
I had dual 5 footers on the 84 mounted to the flat bed. I never had any issues with ripping them off either. On my 83 its mounted basically to the front bumper. Its going to get moved eventually to the front part of the bed. For the bracket you are thinking of why not just go to a truck stop? They sell those mounts for like $5 with all the mounting hardware included. It sure beats building them sometimes just for simplicity's sake.
