I'll try to find the link, but when the time comes, I'm planning on using a premade bench seat from this company that makes them. they come in different widths and have seat belts already installed and those stay with the seat. The have special brackets to place in the floor so that the seat is removeable yet secure. Thaet are not overtuffed or styled so they will look like the originals except with the seat belts. They come in different colors but I'll end up painting them to look original and then have them reupholstered.

Found it.
http://www.guytoys.net/auto/adnik_quick_release.htm
Above is the bracket kit.
http://www.guytoys.net/qualitex/universal_bench_seat.htm
above is the seat. You'll see it comes in diff widths AND heights! You can add some tubing to the ends to recreate the original suburban armrest/bar

grin