I just acquired a 1970 2800 and I'm in the market for a new front windshield too.. here's an interesting discovery I stumbled across... This seller on eBay (based in Atlanta) has a E3 windshield for sale:
Find many great new & used options and get the best deals for BMW 2500 2800 3.0S E3 Windshield 1969-77 New at the best online prices at eBay! Free shipping for many products!
www.ebay.com
If you read his description carefully, there's potentially a very important detail: he claims this is new production glass from Scandinavia, built to original BMW spec. I'm willing to do some research for this site, and see what's the full story is.
I wonder if they are making E3, E9 and other BMW glass? That might be a game changer for several projects on this site.
JP
(BTW, since you're in OC, and I'm in redondo beach - we might eventually cross paths at Cars & Coffee in San Clemente. If you have a build thread here in the forums, I'd be interested to take a look at your project...)