I sold this ute to Go_The_Datto over a year ago but the window was already in it when I bought it as an unfinished CA18 project. It was originally done by a guy called Andrew in Echuca. I spoke to him a couple of times and believe he modified the mechanism from an old HQ-HZ Holden station wagon tailgate. It was wired up and I got it going up and down by touching the wires directly to a battery but the whole thing needed a little finishing off. Essentially a channel was fitted around the original window frame, some box tubing added with some rails and I bought some felt type pinch weld to go in the channel to hold the window in place and stop it leaking. I never sprayed it with water so not sure how water tight it was, but window sat in the tray behind a false wall (rather than inside the cab like the Pimp my ride S10 pickup) so it probably just needed a drainage hole in the tray and plenty of body deadner to seal it all up. Although it wouldn't see too much water on a normal rainy day anyway as it sits an inch or so inside the roof line. It was a cool idea but I wasn't sure what an engineer would think of it, whether you would end up with wind swirling at the back of your head if you were driving with it down and whether it was really worthwhile
for anything other than novelty value....must admit I never thought of installing a pool table in the tray to get the full advantage of it though.
Hopefully go_the_datto will update us on the progress soon.