Here are some that I have done,
'86 Std cab,
'87 2wd,
.
This is one I did w/an ice chest for my '91,
.
I started with an ammo can for the base,
and made the shifter area out of wood,
.
I would suggest you start out by start making a cardboard template like this,
A template will make it easier to get the design, size, and arm rest height right, before you start building the actual one.