So we've got the window and installed it.
Here's how we did it:
We contacted a company here in Seattle that happens to fabricate polymers for Boeing. They have a public-facing business called Fremont Laser & Design. Smart and dedicated folks. Call them and tell them we sent you (they'll know who we are.)
Keep in mind, they were NOT able to duplicate the exact design of the original double-pane window. They were only able to duplicate the shape and curve of the outer window. As you'll see in the pics below, it worked for us.
Also, they didn't cut the groove on the top of the window that fits the window into the long top mount bracket (on top of the van) that helps keep the window in place as well as give the pivot-like functionality of opening the window. We didn't have the bracket so we just used epoxy to mount to where the bracket used to be and then a silicon sealant for good measure.
They took measurements of the original window and curvature. We also asked them to measure where the holes should be for those that still have the original hardware ( which we do not.) This is so that anyone on this forum can order from them and get not only the window but the pilot holes drilled for the mounting hardware.
https://drive.google.com/file/d/0B3slf73n3IHyM05qRDc2OUl6TEE/view
Here's what the window looks like:
https://drive.google.com/file/d/0B3slf73n3IHyUXBZZzZkVkR3d2s/view
https://drive.google.com/file/d/0B3slf73n3IHyQmVYaV84eEVkZGM/view
https://drive.google.com/file/d/0B3slf73n3IHySFpwWUphdnpiUk0/view
Here's what it looks like the way we mounted it (don't laugh, we didn't have the original parts so had to hack it a bit):
The process of mounting it took me 2 days. The hard part was getting the angle for my custom brackets (made of wood and composite shims) to make the metal brackets flush with the window.
https://drive.google.com/file/d/0B3slf73n3IHyVC1tUWhGV3RVV0E/view
https://drive.google.com/file/d/0B3slf73n3IHyZWZndkpWTGxVeUE/view
The outside mount
https://drive.google.com/file/d/0B3slf73n3IHyT1JXRVNiOVFXTU0/view
If anyone orders from them and is interested in the process on how we did the mount, let me know and I'll walk through it with a video or something. It's too long to post unless there's interest.
The upside: there's a window in place of duct tape and cardboard.
The downside: it won't open. Since they don't make the parts anymore (at least we couldn't find them) we had to hack it.
The moral: Keep your windows closed and if you don't, make sure you save every piece of hardware.
Total cost: around $600. However, since we did all the hard work they said they would charge everyone else about half that price.
We took it on a 10 day trip up and down the pacific coast highway 101 and it survived perfectly.
Hope this helps. Thanks to everyone for all your help along the way.