Ok so, hinges have been a nightmare. My beautiful brass 3/4" x 4" hinges have been discontinued and are getting really hard to find. I did manage to get 28 of them but with the new batch going online today I used up more than half.
The good news is that I found an alternative that doesn't compromise the quality of the cases - in my view it is actually an improvement. It's called a barbed or kerf-cut hinge. It fits into a slot on the inside of the case so the entire hinge is hidden from view except for the knuckle. If I use the offset variety the case will still open 180 degrees to lay flat when it's open and it exposes a lot of wood that was previously hidden behind the brass piano hinge. I have to buy a special blade and arbor to cut the slots for them but the hinges themselves are easy to find and I can get them in bulk.
I'll put pictures up when I've completed a couple and tested them out.
Since I've been out for so long and there were a number of people waiting I expect this batch to go fast so I'm already starting another one.