Given the overwhelming amount of available literature on Logos I am a little surprised not to see Metzgers and Alands introductions to textual criticism of the new testament. There are of course several good books available already, but I would very much like to see those two as well.
http://books.google.com/books?id=2pYDsAhUOxAC
http://books.google.com/books?id=6De-QgAACAAJ
I would gladly preorder if it helps – keep me posted :-)