Gimmie a few hours/maybe a day, and I can post some pics.
I am using 5 point Beard harnesses with the factory rear seat.
I scrounged my garage and came up with three (found the fourth later) shock bolts from my old 92 bronco that thread into the stock seatbelt holes.
took a flat bar 3/16 thick and drilled it to go over the vertical seatbelt bolts.
then took standard shock tab mounts and welded where they needed to be for the lap portion of the harness, and for the shoulder belts I welded two extended shock mounts to the top tube of the stock seat frame in a vertical manner for those to mount.
for the crotch strap I have it hooked under the front with a tab on the front of the seat frame. hard to visualize but as i said I can get a pic up today or tomorrow, I have a similiar setup next to it for my daughter who is still in a 5 point seat and just use the latch mechanism from her kid seat. took me some time but I am really pleased how it turned out.
cheap too, and when the little girl outgrows her seat and needs a booster I can just bolt up my other harness for her.
the beard harness is the full race latch style(forget the term) but my 7 year old son has no probs getting in and out, then he helps his lil sis.