Seats, Racing Harnesses and Cup Holders
My Cup Holder is a $41 "Think Outside" PVC Locker purchased at WalMart.  It will be strapped to D-Rings on top of the tunnel.  The locker can be removed and set in the bed for more room to tie down other internal cargo, or left in place for towing accessories, tools, or mountain climbing equipment.  This item solved one of our bigger problems - where to put our coffee cups.
Right Front Seat Frame and Seat
2-inch angle iron and 1-inch square tubing were welded together to straddle the height different between the inboard and outboard mounting points.
Right Rear Seat Sitting on mounting rails purchased with the Euro-style, Leatherette racing seats from Summit Racing.  Note, they are sitting in place, but not yet installed.
These Euro-style seats were purchased so we could install 4-point seat restraints.  The rear seats are an easy fit.  The front seats are a very tight fit.  Serious consideration was given to go with standard seats and belts after the first test-fit, but we managed to design a configuration that will work.  It is very tight and may not suit anyone else's taste!  Copy-cats beware!
The racing harnesses are 2-inch RCI (Racers Choice) Four Point harnesses.  They attached at four points to the body, and were easy to install.  We felt like the places in Idaho where we intend to drive this vehicle were enough reason to go with racing harnesses.  The bottom line is - we want to stay in our seats no matter what.  Now we will.  We used 3/8" stainless steel bolts with stainless washers and ny-lok nuts.