New developments this morning that may be of interest:

(1) In an effort to be more flexible and consider vinyl-clad (as
RicodJour suggested), my wife called all around the area to HD and
others listed as selling Andersen. No one we've contacted has an
example to show us. One installer gave us an address of an install
they did to go look at. It's in Baltimore (We're in DC, and no, it
isn't all the same metro area.) That should give you an idea how
common what we're looking for is.

Exasperated, she called Andersen HQ, and was forwarded to the Carlisle
PA office, where they distribute for our region. They confirmed they
don't sell many vinyl-clad wood gliders in our region. Well, we're
thinking of dropping $20K on buying windows from you, and we'd like to
see one first, can you arrange to get one to our contractor for
inspection, she said. His response,

"No, Andersen doesn't have a program to do that."

Keep in mind, they're shipping millions of dollars worth of windows to
the DC area every month. They can't squeeze an extra window on one of
those trucks? Now, I don't think that bodes well for service in the
future.

Compare that response to the response to my experience talking to
Marvin in the original post for this thread....

(2) Turns out there is a lumber yard with Loewen gliders in the
showroom in N VA that I'm headed out to look at on my lunch hour.