Sent them digital photos, dimensions, and a description of what I'm looking for. So the fishing line is in the water!
One promising thing-- the window guy says there's a good chance that the big honking ugly metal extrusions on the outside are hiding the original wood trim. "Those people [metal replacement window installers] don't like to do any more work than they have to."
So I can hope.
I'd still have to look into the big wood window manufacturers like Pella, Marvin, JenWeld, etc. But so far, going by their websites, only Anderson seems to have the three-over-one lights pattern I want as a standard. And if I can get units that actually fit the openings, how great would that be?
It'll be interesting seeing what the custom millwork guys come up with. Keeping in mind, of course, that they don't install . . .