I know that I replaced my back-right window in my 93 ford explorer with plexi and it worked out great. I spent 17$ on the entire setup. Plexi and caluk and clear duct tape and black paint. Keep in mind this is the rear quarter panel glass, a big window.
I simply traces the opened in carboard, cut it out, traced it on plexi, useda 2$ plexi/plastic cutter razer, snapped it, used likea 8$ dremil and my hand to smooth the edges, layed the caulk, put the window in place, and duct taped it. 2 days later i removed the duct tape a,d used some like 1 or 2$ pin stripe tape to make an inner border like most suv windows have and taped it off a little and sprayed it in black. at day and night time when its not wet you have no idea its not the stock window. it looks perfect.
My idea?
A truck has 4 main windows but only three really play a role unless you chop top. The two doors and the rear window. Now you can get plexi, lexan, cool blue etc in tinted colors like a light black tint etc...
So... why not attempt to make one window... and if it doesnt work then all you wasted is like 20$... but make one window for a door and see if its possible to make them from one of these materials. It would take quite a long time for one of these to fade, which is the only problem i can think of that someone might say, and i know you say "but the glass has a small bend in it" well its not that mich of a bend if any, and you can use the stock glass to help... lay the plexi over the stock and LIGHTLY heat it up using like a heat gun.
Thats just my idea of how you could do it.. if it worked then do the other door and rear glass by making it a solid one piece.