Russell,
You might want to see if you can pick up a 2wd 22re longbed tank. I believe they don't hang down below the frame rails - because of this, you will lose about 5 gallons though. I'm looking into this for my '85.
Uh, just a after thought: did they make a 2wd long bed with a 22re anywhere between '84 and '88? I think the only ones I've seen are carburated. You might have to stick with a 4x4 tank....
P.S. Fabbing lines is easy to do. I just took some measurements, made some bends with a handheld tubing bender and added some Earls fittings.