Do you have the art for it?

We'll take the physical challenge

In all seriousness have you seen this thread?
https://pinside.com/pinball/forum/topic/ted-with-a-pinball-idea-and-i-need-your-opinion
If you can find the art Ted can get one made up

This is a long shot.
Some might not be aware, but NOS versions of this backglass are VERY RARE now.
This is a $550 backglass minimum, no shipping included.
There were not that many extras made.
The game production was just too low.
I really mean that, this is a glass when few extras were available got "scooped up" fairly quickly even at $250 about 15+ years ago.
Maybe 10-15?

The ones you see around (Ebay generally or a rare parted game), generally are in "good" shape comparative to other titles.
Used are still around $250 or so, but generally have some edge peeling versus flaking or veining.
It is the FIRST thing to be sold.
I know of several, both they all are in games be prepared for restoration, so they are not going to be parted out.
The other NOS ones are hiding in people's closets, and are not coming out.

But do not lose hope!

Best, cheapest, and fastest solution versus ridiculous internet scouring or someone's belief the backglass is made of pure platinum by weight...
Have a NEW backglass made:
http://bgresto.com/?p=1367

Superb quality, scan completed, should run around $225+shipping.
You and your friend will not be disappointed at the results.
This is not a cheap knockoff, and only a few steps below a full ink screened backglass and whole lot faster.
Expect a turn around of about 4-6 weeks.

Not sure where you're getting your info, but I replaced my blown DD backglass about 5 years ago with a NOS from TNT for about $100 (at the time he had more than 1) so there were some out there and not at $250+. I also scored a NOS set of plastics for $100 from a private seller around the same time as well. I'm not saying that it's raining DD parts, but if you're patient they do turn up and at reasonable prices. Hell, I had a project DD with a nice BG that I couldn't sell for $200 - so that tells me the parts aren't worth what is being claimed.

BGResto is definitely one option if you need it now - but one thing I have learned is that patience is key in finding parts for odd-ball games.

The OP never mentioned patience.

I said the same thing about NOS EBD backglasses (all three types) 15 years ago and NOS plastic sets for other various games not reproduced 5 years ago. Times have changed. Used glasses are not always a preferred option for this game. Ask Todd what he has now, they are long gone. I know, I bought one too.
I bought a lot of glasses when they were cheap.

If a person has a source for a NOS glass at $100 give the lead to the owner. I gave a fantastic alternative, which the quality will match a NOS glass in this game. Wait 6 weeks and pay less, or wait 6 months to 2 years, and pay more. This reproduction will be more hardy to the environment as well.

Prices don't EVER go down on backglasses. They go UP, forever, even after CPR or Shay makes reproductions on popular games. Their costs go UP as well, biannually.