I dunno, though. I don't see the benefit in k-12 of studying just one religion. If anything religions should be compared and contrasted. How often do world events require us to know about St Paul? On the other hand, people boggle over the difference between Sunni and Shia Muslims every day.
For that reason, I don't think you can do it responsibly without making it a class on all the major religions. Maybe after that you could offer advanced courses in individual religions, but are there books like this on Islam or Buddhism?
Anyway, like the article says, kids simply don't have the open slot for such in-depth study of one religion. Heck, I'd much rather see kids taking home economics or just regular economics. We already spend too much time turning out kids that know archaic details of history and who can't feed themselves or balance their checkbook...