I alluded to this in my last post, but I felt I should make it clear for people who didn’t read behind the cut:
A lot of information around the net – including my own Inscription guide, currently – says that Scribes will be getting an extra Major Glyph slot that no-one else gets.
This is no longer true – at least as far as I can determine. The trainers no longer offer it as an ability, it’s been deleted from WoWhead’s WotLK subsite, and there’s been no official reference to it for a long time.
Unless it’s put back in in a late-breaking change, I think it’s fairly conclusive that the extra glyph slot for Scribes has gone the way of the dodo.
There’s a new version of the Inscription Guide, Version 1.1, available for download, updating the above information and adding a few other refinements and clarifications.