In my research on the use of God's name in the New Testament I came across reference to the Tetragram Gospels. You can imagine my excitement that this obscure twelfth century manuscript of the gospels might contain the tetragrammaton. Alas, when I eventually got to look at the microfilm it turned out that it was only called the Tetragram Gospels because it only contained the four (tetra) gospels.
For your interest it was written by a scribe named Joseph and its main interest is that the passage at Luke 22:43-44 describing Jesus' "bloody sweat" is marked with asterisks to indicate its spurious nature. It can now be found as ms 828 in the Edgar J. Goodspeed Collection of the University of Chicago Library.
Earnest