David C. Parker is quite skeptical that either Vaticanus or Sinaiticus were a result of this edict. It may have involved a New Testament only, or a lectionary, and it is hard to consider the large parchment volumes as portable. Parker gives a number of reasons and then found that there was a similar position in:Victor Constantinus Maximus Augustus to Eusebius.
In the city named after us [Constantinople] a great crowd of people have, thanks to the providence of the Saviour God. devoted themselves to the most holy Church. Since everything in the city is growing so quickly, it is obviously appropriate to build more churches. Be prepared to act at once on our decision We make known to you that you are to commission fifty volumes which are to be bound in leather, easy to read and (for convenience) portable. They are to be written by craftsmen who are both calligraphers and used to working accurately. They are to be copies of the divine Scriptures, which you well know must be available for reading in church. We have sent written word to the Financial Director of the Diocese, who is to ensure that all necessary materials are provided. So that the written volumes may be prepared very quickly, let this work receive your attention. Moreover by the authority of this our letter you receive the power to requisition two public vehicles to transport them. These are the best means by which the books may be written calligraphically and easily dispatched for our inspection of them. Of course this will be carried out by one of the deacons of your church, who when he comes will experience our generosity.
May God watch over you, dear brother
Thus the emperor instructed. Action immediately followed word, as we sent him threes and fours in curiously worked bindings. David Parker, p. 19-20
Papers Presented to the 10th International Conference on Patristic Studies Held in Oxford, 1987: Historica, theologica, gnostica, Biblica, et Apocrypha
Copies of the Sacred Writings" (VC 4.36): Entire Bibles or Gospel Books?
Gregory Allen Roberts
p. 91-98 (95-96 not online)