Dan,
Sorry I don't know the price. Bob Knight who runs TrainCat just told me he was running the bridges through the etcher on Thursday. He may have to make up instructions or packaging before they go to sale (just guessing). You could e-mail him though, he always responds to mine.
sales@traincat2.com
If I could find a way for his adobe illustrator to read my CAD drawings he was going to make me some things along with his bridges.
That Z scale bridge is a pretty old design, but they would be nice to have in N.