I am re-doing my rear 14" shocks right now and here's what I did.
get some trailer shackles from agriculture store and cut em in half. (these are now the tabs to weld onto the top of your axle and bolt the shocks in)... bottoms are done now.
cut a hole in the flatbed expanded steel and stand shock up through it. Done now.
get trailer leaf springs hangers that are 1.25" wide and bolt them to the top of the shock... weld that to your chassis however you want to. I'm probably gonna use some small tubing and a 1/4" gusset 
man that sounds rad.. got picks? on the inside of your truck bed is there anything sticking up?
